CA2296608C

CA2296608C - Densitometer, test piece for the densitometer, biosensor system, and method for forming terminal of the test piece

Info

Publication number: CA2296608C
Application number: CA002296608A
Authority: CA
Inventors: Shoji Kawanaka; Yoshinobu Tokuno; Kohei Ishida
Original assignee: Kyoto Daiichi Kagaku KK; Matsushita Electric Industrial Co Ltd
Current assignee: Arkray Inc; PHC Corp
Priority date: 1997-07-22
Filing date: 1998-07-15
Publication date: 2004-10-12
Anticipated expiration: 2018-07-15
Also published as: EA002856B1; EP1024358A1; WO1999005516A1; ES2323393T3; AU725457B2; EP2006669A2; EP2056108A1; AU8242198A; EP1024358A4; BR9810794B1; NZ502011A; EP2015068A1; CA2296608A1; KR100675463B1; US6599406B1; ATE427483T1; CN1265194A; KR20010022163A; DE69840703D1; EP2199403A1

Abstract

The present invention provides a test strip and concentration measuring apparatus, a biosensor system and a method for forming terminals of the test strip, where by a component can be measured by fitting the test strip to the component. A type judgement electrode is provided separately from a positive electrode and a negative electrode in a measuring apparatus so as to judge the insertion of a test strip with the measuring apparatus. Thus only when a test strip matching the measuring apparatus is inserted, the type judgement electrode electrically connected to a terminal of the test strip, enabling the measuri ng apparatus to measure a component in a liquid test sample. A measuring apparatus detects a change in calibration curve information selection for selecting calibration curve information corresponding to a production lot of the test strip to compensate for error in a measured concentration value.

Description

DENSITOMETER, TEST PIECE FOR THE DENSITOMETER, BIOSENSOR SYSTEM, AND METHOD FOR FORMING
TERMINAL OF THE TEST PIECE
Technical Field The present invention relates to a test strip and apparatus for measuring concentration of a specific component in a solution with the use of a biosensor, a biosensor system using the concentration measuring apparatus and the test strip, and a method for forming a terminal on the test strip. The solution to be measured is specifically humor, e.g., blood, blood plasma, urine, saliva, etc.
Background Art Measuring apparatuses using biosensors are now in practical use for quantitatively detecting a specific component in humors of living bodies such as blood, urine or the like. In such a measuring apparatus, a compact and disposable test strip is fitted as the biosensor, and for instance, blood is dropped on the test strip to measure concentration of glucose, lactic acid, cholesterol or the like.
The aforementioned method and a structure of the test strip for the concentration measurement are disclosed, for example, in the published specification of Japanese Patent Laid-Open Publication No. 4-357452. The test strip of this prior art is constructed as shown in Fig. 33. Specifically, a conductive carbon paste or the like is screen printed on a sheet of a strip of an insulating base material 2 to form terminals 3, 4 adjacent to each other at one end of the base material 2. The terminals 3, 4 are extended in the longitudinal direction to form a measuring electrode 5 and a counter electrode 6 facing the measuring electrode S at the other end of the base material 2. An insulating layer is formed on the insulating base material except for portions on the terminals 3, 4, the measuring electrode S, and the counter electrode 6. A reaction reagent (not shown) composed of an enzyme, a mediator, etc.
corresponding to a component to be measured is applied on the measuring electrode 5 and the counter electrode 6. A cover 8 is fitted via a spacer 7 over the base material 2 except the terminals 3, 4. A test strip 1 of Fig. 34 is thus obtained. A projection 10 is formed so as to prevent the test strip 1 from being inserted in a measuring apparatus in a wrong direction.
As is revealed, e.g., in the prior art No. 4-357452, the test strip 1 is inserted into a measuring apparatus 20 from the side of the terminals 3, 4 to a setting part 21 of a card-shaped measuring apparatus 20 as shown in Fig. 35. A display part 22 is provided at a surface of the measuring apparatus 20 to display measurement results. The setting part 21 of the conventional measuring apparatus 20 has a positive and a negative electrode to be electrically connected to the terminals 3, 4 of the test strip 1 when the test strip 1 is inserted in the measuring apparatus 20.
After the test strip 1 is inserted, as is clear from the same prior art No. 4-357452, for instance, blood is spotted on the external end part of the test strip 1, which is aspirated by capillary action to a space 9 formed in the spacer 7. The blood reaches the reaction agent applied on the measuring electrode 5 and counter electrode 6 and reacts with the reaction reagent. A voltage is impressed to the terminals 3, 4 of the test strip 1 from the measuring apparatus 20, whereby a reaction product through a reaction with the enzyme is oxidized. A
current generated in this oxidation is measured at the measuring apparatus 20.
The measured oxidation current is converted to a concentration of the specific component to be measured.

The reaction reagent used is, e.g., one that includes glucose oxidase as the enzyme when glucose in the solution is to be measured, or that includes lactate oxidase, cholesterol oxidase when lactic acid, cholesterol in the solution is to be measured, a:~ disclosed in a published specification of Japanese Patent Laid-Open I~o. 8-278276, As is apparent from the above description, the test strip corresponding to each component to be measured can be obtained by replacing the enzyme contained in the ruction reagent without changing the test stxip 1 structure In other words, the same test strip structure can be made for use with various kinds of components, and the measuring apparatus and manufacturing facility for the test strips can be shared, reducing manufacturing cost.
Although it is ideal that there be an equal demand for test strips loc~
different components, practically, test strips for glucose are required most, while those for lactic acid or cholesterol are less required. if the test strips have the same structure, in the aforementioned in-egular demand, the test strip for the irregular demand can be obtained simply only by changing the reaction reagent.
However, with the same test strip structure it becomes difficult tc>
distinguish between different test strips. It may happen that the lactic acid test strip is inadvertently set in the measuring apparatus even though a concentration of glucose is necessary. Thus, an incorrect result is obtained.
Summary of the Invention The present invention is devised to solve the <rbove-described inconvenience and has for its object to provide a concentration measuring apparatus, a test strip for use in the measuring apparatus, a biosensor system, and a method for forming terminals on the test strip whereby a target component is measured with the test strip fit thereto.
In accordance with one aspect of the present invention, there is provided a concentration measuring apparatus for measuring the concentration of a specific component in a liquid sample included in a test strip, the test strip being inserted in the concentration measuring apparatus, the test strip including a reaction reagent which is to react with the liquid sample, the test strip further including a positive terminal and a negative terminal, the concentration measuring apparatus comprising: a positive electrode and a negative electrode for electrically detecting the concentration of the specific component in the liquid sample, the positive electrode being connected to the positive terminal of the test strip, the negative electrode being connected to the negative terminal of the test strip; and a type judgement electrode for judging a type of the reaction reagent on the inserted test strip, tire type judgement electrode being separate from the positive electrode and the negative electrode.
l5 In accordance with another aspect of the present invention. there is provided a test strip to be inserted in the concentration measuring apparatus. 'fhe test strip comprises a type judgement terminal which is to be electrically connected to the type judgement electrode and the positive electrode. By the method, an identification device of the concentration measuring apparatus is let to send out the information corresponding to the test strip.
In accordance with yet another aspect of the present invention, there is provided a biosensor system comprising: a first concentration measuring apparatus co~rrprising the concentration measuring apparatus wherein the positive electrode, the type judgement electrode, and the negative electrode are arranged in this order orthogonal to an insertion direction of a test strip; a first test strip comprising the test strip to be inserted in the first concentration measuring apparatus which includes a tirst terminal to be electrically connected to the positive electrode and the type judgement electrode, and a second terminal to be electrically connected to the negative electrode; a second concentration measuring apparatus comprising the concentration measuring apparatus wherein the positive electrode, the negative electrode, and the type judgement electrode are arranged in this order orthc~gunal to the insertion direction; and a second test strip comprising the test strip to be i~~serted in the second concentration measuring apparatus which includes a first terminal to be electrically connected to the positive electrode and type judgement electrode and a second terminal to be electrically connected to the negative electrode, wherein said biosensor system is so constituted that a concentration of the specific component cannot be measured if the first test strip is inserted in the second concentration measuring apparatus, and if the second test strip is inserted in the first concentration measuring apparatus.
In accordance with yet another aspect of the present invention, there is provided a method for manufacturing the test strip to be set to the concentration measuring apparatus. In the concentration measuring apparatus, tile change jr.idge device: stores a plurality of calibration curve information for compensating for an error in concentration measurement of trre specific component in the liquid test sample; detects a calibration curve information selection change at the type judgement electrode so as to select a required calibration curve information among the plurality of calibration curve information in place of judging the presence/absence of the appropriate test strip change at the type judgement electrode when the concentration measuring apparatus can measure the concentration of only one specific component and the test strip having a reaction reagent which is t<.~ react to the specific component and capable of measuring the concentration of the specific component when inserted in the concentration measuring apparatus; and compensates for the error based on the c<rlibration curve Sa information selected in accordance with the detected calibration curve information selection change. The test strip comprises a type judgement terminal to be electrically connected to the type judgement electrode and allows the change judge device to detect the calibration curve information selection change for selecting the rerauired calibration curve information among the plurality of calibration curve information on the basis of the potential at the type judgement electrode. The method comprises the steps of: applying the reaction reagent on the base material of the test strip; dropping a standard solution having the specific component of which a concentration is known to the applied reaction reagent; and selecting the calibration curve information compensating for an error between a detected concentration based on, the reaction and the known concentration of the specif is component;
and forming the type judgement terminal so that the calibration curve infortmrtion selection change indicating at least the selected calibration curve information is generated at the type judgement terminal.
Brief Description of Drawing These and other aspects and features of tl~e present invention will become clear fi-orn the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:
Fig. 1 is a structural diagram of a concentration measuring apparatus according to a first embodiment of the present invention;
Fig. 2 is a plan view of a test strip to be inserted in the concentration measuring apparatus and fit to concentration measuring apparatus of Fig. 1;
Fig. 3 is a plan view of a test strip to be inserted in the concentration measuring apparatus and not fit to concentration measuring apparatus of Fig. 1;

Sb Fig. 4 is a structural diagram of a concentration measuring apparatus according to a second embodiment of the present invention;
Fig. 5 is a plan view of a test strip to be inserted in the concentration measuring apparatus and fit to concentration measuring apparatus of Fig. 4;
Fig. 6 is a plan view of a test strip to be inserted in the concentration measuring apparatus and not fit to concentration measuring apparatus of Fig. 4;
Fig. 7 is a structural diagram of a concentration measuring apparatus according to a third embodiment of the present invention;
Fig. 8 is a plan view of a test strip to be inserted in the concentration measuring apparatus and fit to the set concentration measuring apparatus of Fig. ~';

Fig. 9 is a plan view of a test strip to be inserted in the concentration measuring apparatus and not fit to the concentration measuring apparatus of Fig. 7;
Fig. 10 is a flow chart of operations for identifying the test strip in the concentration measuring apparatus of Fig. 7;
Fig. 11 is a structural diagram of a concentration measuring apparatus according to a fourth embodiment of the present invention;
Fig. 12 is a plan view of a test strip to be inserted in the concentration measuring apparatus and fit to the concentration measuring apparatus of Fig. 11;
Fig. 13 is a plan view of a test strip to be inserted in the concentration measuring apparatus and not fit to the concentration measuring apparatus of Fig. 11;
Fig. 14 is a flow chart of operations for identifying the test strip in the concentration measuring apparatus of Fig. 11;
Fig. 15 is a plan view of a test strip of a different embodiment to be inserted in the concentration measuring apparatus of Fig. 11;
Fig. 16 is a diagram of a modified example of the concentration measuring apparatus of Fig. 1;
Fig. 17 is a plan view of a test strip fit to the concentration measuring apparatus of Fig. 16;
Fig. 18 is a flow chart showing operations of the concentration measuring apparatus of Fig. 4;
Fig. 19 is a structuraldiagram of a concentration measuring apparatus according to a fifth embodiment of the present invention;
Fig. 20 is a plan view of a test strip to be inserted in the concentration measuring apparatus of Fig. 19;
Fig. 21 is a structural diagram of a modification of the concentration measuring apparatus of Fig. 19;

Fig. 22 is a plan view of a test strip to be inserted in the concentration measuring apparatus of Fig. 21;
Fig. 23 is a structural diagram of a different modification of the concentration measuring apparatus of Fig. 19;
Fig. 24 is a plan view of a test strip to be inserted in the concentration measuring apparatus of Fig. 23;
Fig. 25 is a diagram explanatory of a formation method for forming terminals in each test of Figs. 20, 22, and 24;
Fig. 26 is a diagram explanatory of the formation method for forming terminals in each test of Figs. 20, 22, and 24;
Fig. 27 is a diagram explanatory of the formation method for forming terminals in each test first strip of Figs. 20, 22, and 24;
Fig. 28 is a diagram explanatory of the first formation method for forming terminals in each test strip of Figs. 20, 22, and 24;
Fig. 29 is a diagram explanatory of a second formation method for forming terminals in each test strip of Figs. 20, 22, and 24;
Fig. 30 is a diagram explanatory of the second formation method for forming terminals in each test strip of Figs. 20, 22, and 24;
Fig. 31 is a diagram explanatory of the second formation method for forming terminals in each test strip of Figs. 20, 22, and 24;
Fig. 32 is a diagram explanatory of the second formation method for forming terminals in each test strip of Figs. 20, 22, and 24;
Fig. 33 is an exploded perspective view showing a structure of a conventional test strip (Prior Art);

Fig. 34 is a perspective view of a state when the test strip of Fig. 33 is assembled (Prior Art);
and Fig. 35 is a perspective view of a state when the conventional test strip is set in a conventional concentration measuring apparatus (Prior Art).
Best Mode for CarrXing Out the Invention In the drawings, parts functioning the same or similarly are denoted by the same reference numerals and the description thereof will not be duplicated except what is to be particularly noted.
First Embodiment A test strip and concentration measuring apparatus according to a first embodiment of the present invention are shown in Figs. 1 through 3. An exemplary functioning as a first identification device is a circuit part 111 to be described later which comprises an amplifier 105, an A/D converter 107, a connecting line including an R1 resistor 109, an RZ resistor 110, and a resistor 106. On the other hand, an example of a second identification device is a CPU 108 to be described later. Further, a digital value sent out from the A/D
converter 107 to be described later corresponds to an embodiment of the information corresponding to the test strip capable of measuring the specific component of the liquid test sample.
A concentration measuring apparatus 101 shown in Fig. 1 will be described first. The concentration measuring apparatus 101 has a type judgement electrode 104 in addition to a positive electrode 102 and a negative electrode 103 provided in the conventional measuring apparatus alike. The type judgement electrode 104 is an electrode for judging whether or not a test strip can be measured by the concentration measuring apparatus 101. The positive electrode 102, the type judgement electrode 104, and the negative electrode 103 are arranged in a row orthogonal to a test strip insertion direction I, as indicated in Fig. 1. The concentration measuring apparatus 101 includes therein the amplifier 105, the A/D converter 107 connected to an output of the amplifier 105 via the resistor 106, the CPU
108 (central processing unit), the R1 resistor 109, and the R2 resistor 110. An input terminal lOSa of the amplifier 105 is connected with a reference voltage source Vref, and the other input terminal l OSb of the amplifier 105 is connected with the positive electrode 102. The type judgement electrode 104 is connected to the output of the amplifier 105 via the Rl resistor 109. The negative electrode 103 is grounded and, also a connecting line between the amplifier 105 and positive electrode 102 is grounded via the R2 resistor 110. The CPU 108 controls operations of the concentration measuring apparatus 101, e.g., controls calculation of a component's concentration, as well as judges whether or not the inserted test strip can be measured by the concentration measuring apparatus 101. In other words, the CPU 108 carries out an identification action. However, an identification device performing only the identification action may be provided separately from the CPU 108. Although the identification action will be detailed later, since the digital values are changed based on whether or not the inserted test strip can be measured by the measuring apparatus 101, the CPU 108determines whether or not the test strip can be measured based on a difference of digital values fed from the A/D
converter 107.
In an example of the first embodiment, the R1 resistor 109 is 100kS2, R2 resistor 110 is 100kS2, reference voltage source Vref is O.SV, and the amplifier 105 has SV
source voltage.

The operation of the concentration measuring apparatus 101 constituted as above will be depicted below. Figs. 2 and 3 are simplified diagrams of test strips 115, 121.
The fundamental structure of each test strip 115, 121 is the same as that of the conventional test strip 1 illustrated in Figs. 33 and 34. Reference numerals 116, 122 in Figs. 2 and 3 5 correspond to the reaction reagent described earlier. The measuring electrode 5 and counter electrode 6 are hidden by the reaction reagents 116, 122, and are not shown in the drawings.
Test strip 115 contains a reaction reagent 116 that can be measured while test strip 121 contains a reaction reagent 122 that cannot be measured by the concentration measuring apparatus 101. That is, the test strip 115 fits the concentration measuring apparatus 101 but 10 test strip 121 does not.
In the test strip 115, a positive terminal 117, a type judgement terminal 118, and a negative terminal 119 are formed in a direction orthogonal to the set direction I of the test strip 11 S so that they are electrically connected to the corresponding positive electrode 102, type judgement electrode 104, and negative electrode 103 of the concentration measuring apparatus 101. The positive terminal 117 and type judgement terminal 118 of the test strip 115 are formed integrally into one terminal, so that the positive terminal 117 and type judgement terminal 118 are electrically connected to the measuring electrode 5, and the negative terminal 119 is electrically connected to the counter electrode 6.
Meanwhile, the test strip 121 in Fig. 3 has no terminal corresponding to the above type judgement terminal 118, with having only the positive terminal 117 and negative terminal 119. In other words, the test snip 121 is the same as the conventional test strip 1.

When the test strip 115 is inserted in the concentration rneasurirtg apparatus 101, the positive electrode 102 and positive terminal l 17, the type~udgerllellt electrode 104 and type judgement terminal 118, and the negative electrode 103 and negative terminal 119 are electrically connected with each other respectively. Since the positive terminal 117 and type judgement terminal 118 are integrally formed in the test strip 115, the positive electrode 102 and type judgement electrode 104 are short circuited at the concentration measuring apparatus 101.
When the test strip 115 is inserted, a feedback circuit is formed in the amplifier 105 via the R1 resistor 109 because of the short circuit between the positive electrode 102 and type judgement electrode 104. As a result, the amplifier 105 outputs a voltage Vi exceeding the reference voltage Vref due to resistance of the R I resistor I 09, R2 resistor I 10 and the test strip 115. The A/D converter 107 digitizes the voltage Vi and sends a digital value DI
corresponding to the voltage Vi to the CPU 108.
The CPU 108 has a preset digital value Dl. When the digital value Dl is supplied from the A/D converter 107, the CPU 108 judges that the supplied digital value is equal to Dl, and accordingly detects that the test strip 1 l5 with the measurable reaction reagent 116 is inserted in the measuring apparatus 101. Measurement of the cancentration of the component can start.
On the other hand, if a test strip other than the test strip 115, c.g., the test strip 121, is inserted in the measuring apparatus 101, the positive electrode 102 and type judgement electrode 104 of the measuring apparatus 101 are not short circuited because the test strip 121 does not have the type judgement terminal 118. Thus the aforementioned feedback circuit is not formed in the amplifier 105. The input terminal l OSb of the amplifier 105 connected to the positive electrode 102 is consequently grounded via the R2 resistor 110. In the absence of the feedback circuit, a potential difference between the input terminal lOSb and reference voltage Vref causes the amplifier 105 to output a voltage V2 which is larger than the voltage Vi, considerably large as compared with the reference voltage Vref and close to the. source voltage of the amplifier 105. The A/D converter 107 digitizes the voltage V2 to a digital value D2 and sends the value D2 to the CPU 108.
The sent digital value D2 is different from Dl, and therefore the CPU 108 detects that the test strip 121 with the unmeasurable reaction reagent 122 is inserted in the measuring apparatus 101. The concentration measurement is hence not executed.
The circuit corresponding to a first identification device 111 is used also to measure the component when the test strip 115 with the measurable reaction reagent 116 is inserted in the measuring apparatus 101. An exemplary measurement operation will be discussed hereinbelow, in which the liquid test sample dropped on the test strip 115 is blood and the component to be measured is glucose.
When the test strip 115 is set to the concentration measuring apparatus 101, the feedback circuit is formed in the amplifier 105 because of the short circuit of the positive electrode 102 and type judgement electrode 104 of the measuring apparatus 101 as described hereinabove The reference voltage Vref of the amplifier 105 is impressed to a part of the test strip 115 where the reaction reagent 116 is applied. In the meantime, blood is dropped on the reaction reagent 116. A voltage corresponding to the oxidation current through the reaction between the reaction reagent 116 and blood is output from the amplifier 105 to the A/D
converter 107, similar to the prior art. Needless to say, the oxidation current varies in accordance with a concentration of glucose in the dropped blood. The CPU 108 converts the digital value sent from the A/D converter 107 corresponding to the concentration of glucose in the blood to a blood sugar value. The blood sugar value as a measurement result is displayed at the display part 22.
According to the above-described first embodiment, only when the test strip 115 equipped with the measurable reaction reagent 116 is inserted in the measuring apparatus 101, is measurement operation for the component carried out. Therefore, incorrect measurements can be avoided even if a test strip designed for measurement of lactic acid is inadvertently set to the measuring apparatus 101 instead of a glucose test strip.
Second Embodiment A concentration measuring apparatus and a test strip used in the concentration measuring apparatus according to a second embodiment of the present invention are indicated in Figs. 4-6 and 2. A CPU 134 to be described later corresponds to an embodiment of an identification device. At the same time, a digital value output from the A/D
converter 107 to be described later is an example of the information of the detecting part of the positive electrode.
A concentration measuring apparatus 131 shown in Fig. 4 will be described. The concentration measuring apparatus 131 is provided with the type judgement electrode 104.
As indicated in Fig. 4, the type judgement electrode 104, positive electrode 102, and negative electrode 103 are arranged orthogonally in a row in this order along the insertion direction I
in the concentration measuring apparatus 131. The type judgement electrode 104 in the measuring apparatus 131 is connected to the input terminal l OSb of the amplifier 105 via a switch 132 and also grounded via a switch 133. These switches 132, 133 are individually turned ON, OFF under control of a CPU 134. The output of the amplifier 105 is connected to the CPU 134 via the A/D converter 107.
S
The CPU 134 controls concentration measurement when a test strip with a measurable reaction reagent is inserted in the measuring apparatus 131. Specifically, as shown in Fig. 18, when a test strip is mounted to the measuring apparatus 131 in step 1 the CPU
134 turns OFF
both of the switches 132, 133 in step 2 a predetermined time later after the test strip is perfectly inserted in the apparatus 131. In step 3, a digital value DS
supplied in this state from the A/D converter 107 is stored in the CPU 134 (referred to the operation of the steps 1-3 as "a first operation" hereinafter) . A predetermined time after the digital value DS is stored, the CPU 134 turns ON the switch 132 and keeps the switch 133 OFF in step 4, and stores a digital value D6 fed in this state from the A/D converter 107 in step S (referred to the operation of the steps 4 and S as "a second operation") . A predetermined time after the digital value D6 is stored, the CPU 134 turns OFF the switch 132 and turns ON
the switch 133 in step 6. A digital value D7 from the A/D converter 107 is then stored in step 7 (referred to the operation of the steps 6 and 7 as "a third operation"). In step 8, the CPU 134 decides whether or not the digital values DS-D7 are totally equal, and judges that the test strip having the measurable reaction reagent is inserted to the measuring apparatus 131 only when the digital values DS-D7 are all equal. Then the CPU 134 starts to measure the component in step 9. In other cases than when all of the digital values DS-D7 are equal, in step 10, the CPU 134 judges that the test strip with the unmeasurable reaction reagent is inserted in the measuring apparatus 131.

The concentration measuring apparatus 131 of the above constitution operates in a manner as will be described below. In Figs. 5 and 6, test strips 141, 145 to be inserted in the concentration measuring apparatus 131 are illustrated in a simplified fashion, which are basically similar structure to the conventional test strip 1 in Figs. 33 and 34. Reference 5 numerals 142, 147 in Figs. 5 and 6 correspond to the reaction reagent.
Although not shown in the drawings, the measuring electrode 5 and counter electrode 6 are arranged underneath the reaction reagents 142, 147. In the test strip 141, the measurable reaction reagent is applied. The component in the liquid test sample cannot be measured even if the test strip 145 or the test strip 115 of Fig. 2 is set to the measuring apparatus 131.
The positive terminal 117 and negative terminal 119 are formed in the test strip 141 orthogonal to the insertion direction I to be electrically connected to the positive electrode 102 and negative electrode 103 of the measuring apparatus 131. In other words, the test strip 141 does not have a terminal electrically connectable to the type judgement electrode 104 of the measuring apparatus 131.
In contrast, the test strip 145 has a negative terminal 146 and the positive terminal 117. The negative terminal 146 is electrically connected to the type judgement electrode 104 and negative electrode 103 of the measuring apparatus 131 thereby to short circuit the type judgement electrode 104 and negative electrode 103. The positive terminal 117 is electrically connected to the positive electrode 102 of the measuring apparatus 131.
When the test strip 141 is set to the measuring apparatus 131, the positive electrode 102 of the measuring apparatus 131 is electrically connected to the positive terminal 117 of the test strip 141, and the negative electrode 103 of the measuring apparatus 131 is electrically connected to the negative terminal 119 of the test strip 141. The type judgement electrode 104 of the measuring apparatus 131 has no electric connection. Therefore, even when the CPU 134 carries out the first through third operations after the test strip 141 is completely inserted in the apparatus 131, the digital values DSD7 output from the A/D
converter 107 never change. The CPU 134 thus judges based on the absence of a change in the digital values DS-D7 that the test strip 141 with the measurable reaction reagent 142 is inserted in the measuring apparatus 131. Measurement of the component can now start.
When the test strip 145 is set to the measuring apparatus 131, the type judgement electrode 104 and negative electrode 103 of the measuring apparatus 131 are electrically connected to the negative terminal 146 of the test strip 145. Consequently the type judgement electrode 104 and negative electrode 103 of the measuring apparatus 131 are short circuited, and the positive electrode 102 of the measuring apparatus 131 and positive terminal 117 of the test strip 145 are electrically connected with each other.
After the complete setting of the test strip 145, the CPU 134 executes the above-described first through third operations. Since the type judgement electrode 104 and negative electrode 103 of the concentration measuring apparatus 131 are short circuited, and the switch 132 at the input of the amplifier 105 is kept OFF in the first and third operations, the digital values DS, D7 output from the A/D converter 107 do not change. However, the switch 132 is brought into the ON state when the CPU 134 performs the second operation, and the type judgement electrode 104 and negative electrode 103 of the measuring apparatus 131 are short circuited and grounded, whereby the input of the amplifier 105 is grounded. As a result, the digital value D6 sent from the A/D converter 107 in the second operation becomes different from the digital values DS, D7.

The CPU 134 judges from the fact that all of the digital values DS-D7 are not equal that the test strip 145 is one not equipped with the measurable reaction reagent 142 and component measurement is not performed.
S When the test strip 115 shown in Fig. 2 is set to the measuring apparatus 131, the type judgement electrode 104 and positive electrode 102 of the measuring apparatus 131 are electrically connected to the positive terminal 117 and type judgement terminal 118 of the test strip 115. Consequently, the type judgement electrode 104 and positive electrode 102 of the measuring apparatus 131 are short circuited. The negative electrode 103 of the measuring apparatus 131 is electrically connected to the negative terminal 119 of the test strip 115.
After the test strip 115 is completely set, the CPU 134 executes the first through third operations as described earlier. Since the type judgement electrode 104 and positive electrode 102 of the measuring apparatus 131 are short circuited, the digital values DS, D6 sent out from the A/D converter 107 do not change in the first and second operations. On the other hand, the switch 133 is turned ON when the CPU 134 executes the third operation, and moreover, since the type judgement electrode 104 and positive electrode 102 of the measuring apparatus 131 are short circuited, the input of the amplifier 105 becomes grounded. The digital value D7 from the A/D converter 107 in the third operation is consequently different from the digital values DS, D6.
The CPU 134 judges from the fact that the digital values DS-D7 are not the same that the test strip 115 is one without the measurable reaction reagent 142, and does not start the component measurement.

The circuit constitution of Fig. 4 enables also a measurement of a concentration of the component. In order to measure the concentration, the CPU 134 performs the first operation, turning the switches 132, 133 OFF. For example, blood is dropped onto the reaction reagent 142 of the test strip 141 to measure the concentration of, for instance, lactate in the blood.
The measurement of the concentration is substantially not different from the earlier described operation with respect to the first embodiment, the description of which is accordingly omitted here.
According to the second embodiment as above, only when the test strip 141 with the measurable reaction reagent 142 is inserted in the measuring apparatus 131 can the concentration be measured. Therefore, incorrect insertion of a test strip designed for a different measurement is prevented and a wrong result cannot be obtained.
Since the CPU 134 obtains the digital values DSD7 as above in the second embodiment, types of the test strips for the measuring apparatus 131 can be identified if the CPU 134 is adapted to recognize beforehand types of test strips corresponding to the above digital values DS-D7.
Third Embodiment A concentration measuring apparatus and a test strip for the concentration measuring apparatus according to a third embodiment of the present invention are shown in Figs. 7-9.
A CPU 153 described later corresponds to an example of a potential judge device.

A concentration measuring apparatus 1 S 1 in Fig. 7 will be described. The concentration measuring apparatus 151 similarly includes a type judgement electrode 152. As shown in Fig. 7, in the concentration measuring apparatus 151, the positive electrode 102 and negative electrode 103 are arranged orthogonal to the test strip insertion direction I, and further a first type judgement electrode 152a, a second type judgement electrode 152b and a third type judgement electrode 152c are disposed at an inner side of the measuring apparatus 151. The first type judgement electrode 152a, second type judgement electrode 152b, and third type judgement electrode 152c are generically referred to as the type judgement electrode 152.
The positive electrode 102 is connected to the input of the amplifier 105. The output of the amplifier 105 is connected to the CPU 153 via the A/D converter 107. The negative electrode 103 and third type judgement electrode 152c are both grounded. On the other hand, the first type judgement electrode 152a and second type judgement electrode 152b are connected to the CPU 153 via corresponding connecting lines 154, 155 to which a voltage of +SV is normally applied through respective resistors.
The CPU 153 controls, as will be described hereinbelow, concentration measurement of the component in the liquid test sample only when a test strip having a measurable reaction reagent is inserted in the measuring apparatus 151. More specifically, referring to Fig. 10, when a test strip is set to the measuring apparatus 151, the CPU 153 detects each potential of the first and second type judgement electrodes 152a, 152b obtained via the connecting lines 154, 155. Only in a state of an "appropriate test strip set potential", which is a potential state achieved when a proper test strip is set, that is, the potential of the first type judgement electrode 152a is a high level and that of the second type judgement electrode 152b is a low level, the CPU 153 recognizes that the test strip set in the measuring apparatus 151 is one with the measurable reaction reagent, and starts measuring the component in the liquid test sample. If the first and second type judgement electrodes 152a, 152b are not in the above potential state achieved by the proper test strip, the CPU 153 displays, e.g., a warning and refrains from the measurement.

In this embodiment, the CPU 153 is used to judge the potential of the type judgement electrode 152. However, the present invention is not limited to this arrangement and a potential judge device simply for judging of the potential of the type judgement electrode 152 may be provided separately within the measuring apparatus 151.
In addition, a count of the type judgement electrodes is not limited to 3.
Four or more type judgement electrodes may be formed to meet a count of types of test strips to be identified, in which case at least one combination of potentials of the type judgement electrodes is adapted to be the above appropriate test strip set potential.
The operation of the concentration measuring apparatus 151 will be discussed.
Figs. 8 and 9 are simplified diagrams of test strips 161, 165 to be set to the concentration measuring apparatus 151. The test strips 161, 165 are fundamentally similar structure to the conventional test strip 1 of Figs. 33 and 34. Reference numerals 162, 166 of Figs. 8 and 9 are reaction reagents described earlier. The measuring electrode 5 and counter electrode 6 are hidden by the reaction reagents 162, 166 and not illustrated in the drawings.
The test strip 161 is one having the measurable reaction reagent applied thereto, and the component in the liquid test sample cannot be measured by the test strip 165 even when the test strip 165 is inserted to the measuring apparatus.

The positive terminal 117 and negative terminal 119 are formed in the test strip 161 to be electrically connectable to the positive electrode 102 and negative electrode 103 of the measuring apparatus 151 when the test strip 161 is completely inserted to the measuring apparatus 151. Moreover, a first type judgement terminal 163a is formed in the test strip 161 to be electrically connected with the first type judgement electrode 152a of the measuring apparatus 151 A second type judgement terminal 163b provided in the test strip 161 is electrically connectable to the second and third type judgement electrodes 152b, 152c of the measuring apparatus 151. The first and second type judgement terminals 163a, 163b are referred to altogether as a type judgement terminal 163.
While the test strip 161 is perfectly inserted to the measuring apparatus 151, the second type judgement electrode 152b and third type judgement electrode 152c of the measuring apparatus 151 are short circuited by the second type judgement terminal 163b.
The potential of the second type judgement electrode 152b becomes the low level because the third type judgement electrode 152c is grounded.
Meanwhile, although the first type judgement electrode 152a is connected to the first type judgement terminal 163a of the test strip 161, the first type judgement electrode 152a is maintained at +SV because the first type judgement terminal 163a has no electric connection.
Accordingly, the CPU 153 judges that the first type judgement electrode 152a is the high level and the second type judgement electrode 152b is the low level, namely, the appropriate test strip set potential is satisfied. The CPU 153 recognizes that the test strip inserted to the measuring apparatus 151 is one equipped with the measurable reaction reagent, thereby starting the measurement of the component in the liquid test sample.

The test strip 165 has the positive terminal 117 and negative terminal 119, similar to the test strip 161. The test strip 165 also has a first type judgement terminal 167a, a second type judgement terminal 167b and a third type judgement terminal 167c which are electrically connectable to the first type judgement electrode 152a, second type judgement electrode 152b and third type judgement electrode 152c of the measuring apparatus 151 respectively when the test strip 165 is completely set to the measuring apparatus 151. These first, second, and third type judgement terminals 167a, 167b, 167c are independent of one another without any mutual electric connection.
While the test strip 165 in the above constitution is completely inserted to the measuring apparatus 151, because of the absence of the mutual electric connection among the first, second, and third type judgement terminals 167a, 167b and 167c of the test strip 165, the first type judgement electrode 152a and second type judgement electrode 152b of the measuring apparatus 151 are maintained in the state with the +SV applied thereto.
Therefore, the CPU
153 judges that the first and second type judgement electrodes 152a, 152b are both the high level, thereby recognizing that the test strip 165 set to the measuring apparatus 151 is not the one with the measurable reaction reagent. The measurement of the component is not conducted in the CPU 153.
The concentration of the component can also be measured in the circuit constitution in Fig. 7.
For example, blood is dropped on the reaction reagent 162 of the test strip 161, and the concentration of, e.g., glucose in the blood is measured via the positive and negative electrodes 102 and 103 of the measuring apparatus 1 S 1. Since the measurement operation is not fundamentally different from in the first embodiment, the description thereof will be omitted.

According to the third embodiment, only when the test strip 161 with the measurable reaction reagent 162 is inserted in the measuring apparatus 151, component measurement is allowed.
This prevents test strips from being incorrectly used in the testing of components for which they were not designed.
In the above embodiment although at least two type judgement terminals (163a and 163b) are formed in the test strip, a count of the terminals is not restricted. In the event that four or more type judgement electrodes are provided in the measuring apparatus, at least two type judgement terminals are to be formed, so that the potential judge device can judge the appropriate test strip set potential from a combination of connections of the type judgement electrodes and type judgement terminals.
Fourth Embodiment A concentration measuring apparatus and a test strip for the concentration measuring apparatus according to a fourth embodiment of the present invention are indicated in Figs. 11 through 15. A CPU 173 to be described later functions as an example of a change judge device.
A concentration measuring apparatus 171 of Fig. 11 will be depicted below. The concentration measuring apparatus 171 is similarly provided with a type judgement electrode 172. As is shown in Fig. 11, the positive electrode 102, type judgement electrode 172, and negative electrode 103 are arranged orthogonal to the insertion direction I.
The positive electrode 102 is connected to the input of the amplifier 105 having the output thereof connected to the CPU 173 via the A/D converter 107. The negative electrode 103 is grounded. The type judgement electrode 172 is connected to the CPU 173 via a connecting line 174. A voltage of+SV is normally applied to the connecting line 174 via a resistor.
The CPU 173 controls concentration measurement of the component in the liquid test sample only when a test strip with a measurable reaction reagent is inserted in the measuring S apparatus 171. Referring to Fig. 14, the CPU 173 detects potentials of the type judgement electrode 172 immediately after a test strip is inserted to the measuring apparatus 171 in step (designated by S in Fig 14) 21 and when the test strip is completely set to the apparatus 171 in step 22. A change of potentials between the two time points is detected in step 23. More specifically, the CPU 173 judges whether or not the change of the potentials corresponds to an appropriate test strip set change" which is to be brought about only when an appropriate test strip with the reaction reagent measurable by the measuring apparatus 171 is set to the measuring apparatus 171. When the potential change is the appropriate test strip set change, the CPU 173 recognizes that the test strip with the measurable reaction reagent is inserted in the measuring apparatus 171, starting the component measurement. When judging that the potential change is not the appropriate test strip change, the CPU 173 makes, for instance, a warning display, etc, not starting the measurement.
In the above embodiment, the CPU 173 detects potentials of the type judgement electrode 172 at the above both time points to judge the potential change. However, the present invention is not restricted to the embodiment, and a change judge device for detecting the potentials and judging the potential change may be installed separately in the measuring apparatus 171.

The operation of the concentration measuring apparatus 171 will be depicted.
Test elements 181, 185 in Figs. 12 and 13 to be set to the measuring apparatus 171 and illustrated in a simplified manner are fundamentally similar in structure to the conventional test strip 1 of Figs. 33 and 34. Reference numerals 182, 186 in Figs. 12 and 13 correspond to the reaction 5 reagent. The measuring electrode 5 and counter electrode 6 arranged are hidden by the reaction reagents 182, 186 and not seen in the drawings. The test strip 181 has the reaction reagent measurable by the measuring apparatus 171 applied thereto, and the test strip 185 cannot measure the component in the liquid test sample even when set t6 the measuring apparatus 171.
Corresponding to the positive electrode 102 and negative electrode 103 of the concentration measuring apparatus 171, the positive terminal 117 and negative terminal 119 are extended along the insertion direction I in the test strip 181. Moreover, a type judgement terminal 183 is formed in the test strip 181 which is electrically connected to the type judgement electrode 172 of the concentration measuring apparatus 171 only immediately after the test strip 181 is inserted to the measuring apparatus 171 in the insertion direction I. The type judgement terminal 183 is integrally formed with the negative terminal 119.
As is clear from Fig. 12, immediately after the insertion of the test strip 181 to the measuring apparatus 171 along the set direction I, the positive electrode 102, type judgement electrode 172, and negative electrode 103 of the measuring apparatus 171 are located on a line designated by a reference numeral 191, and electrically connected respectively to the positive terminal 117, type judgement terminal 183 and negative terminal 119. Since the type judgement terminal 183 and negative terminal 119 of the test strip 181 are integrated, the type judgement electrode 172 and negative electrode 103 of the measuring apparatus 171 are short circuited immediately after the insertion. Since the negative electrode 103 is grounded, the potential of the type judgement electrode 172 of the measuring apparatus 171 becomes a grounding level, namely, low level.
When the test strip 181 is further inserted in the insertion direction I and fully set to the measuring apparatus 171, the positive electrode 102, type judgement electrode 172, and negative electrode 103 of the measuring apparatus 171 are present on a line 192. In this state, the positive electrode 102 and negative electrode 103 are maintained in a state electrically connected to the positive terminal 117 and negative terminal 119. However, the type judgement electrode 172 of the measuring apparatus 171 is not electrically connected because of absence of a terminal at a position corresponding to the type judgement electrode 172 on the test strip 181. When the test strip is completely set, the potential of the type judgement electrode 172 of the measuring apparatus 171 is changed to +SV, i.e., high level.
As described hereinabove, when the test strip 181 with the measurable reaction reagent 182 is inserted in the measuring apparatus 171, the potential of the type judgement electrode 172 of the measuring apparatus 171 changes from the initial high level to the low level consequent to the insertion of the test strip 181, and returns to the high level again when the insertion is completed, that is, the earlier-mentioned appropriate test strip set change is brought about.
The CPU 173 detects the appropriate test strip set change, thereby recognizing that the test strip 181 with the measurable reaction reagent 182 is inserted in the measuring apparatus 171, and starting the measurement of the component in the liquid test sample.

Incidentally, only the positive terminal l t7 and negative terminal 119 are formed in the test strip 185, without the type judgement terminal 183. Therefore, immediately after the test strip 185 is inserted to the measuring apparatus 171 along the insertion direction I, as shown in Fig. 13, the positive electrode 102, type judgement electrode 172, and negative electrode 103 of the measuring apparatus 171 are located on the line 191, so that the positive electrode 102 and negative electrode 103 are electrically connected to the positive terminal 117 and negative terminal 119 respectively. The type judgement electroclo 172 has no electric connection because the test strip 185 is not provided with a terminal cowesponding to the type judgement electrode 172. The type judgement electrode 172 is accordingly maintained at +5V immediately after the insertion.
When the test strip 185 is further inserted along the insertion direction I
and completely inserted in the measuring apparatus 171, the positive electrode 102, type judgement electrode 172, and negative electrode 103 are on the lure 192, with the positive electrode 102 and negative electrode 103 being kept in the electrically connected state with the positive terminal 117 and negative terminal 1 19 respectively. since a terruinal co~-r~;sponding to the type judgement electrode 172 is not formed in the test strip I 85, the type judgement electrode 172 of the measuring apparatus 171 has no electric connection, and is held at +SV, namely, high level even at the completion of the insertion..
The potential of the type judgement electrode 172 caf the measuring apparatus 171 does not change from the original high level when the test strip 185 with the unmeasurable reaction reagent 186 is inserted in the measuring apparatus 171. Therefore, the CPU 173 recognizes that the test strip 185 having the reaction reagent 186 is set to the measuring apparatus 171 and does not start the measurement of the component in the liquid test sample.

According to the fourth embodiment, the appropriate test strip change at the type judgement electrode 172 of the measuring apparatus 171 is adapted to represent the high level initially, low level subsequent to the insertion of the test strip and high level again when the insertion is completed. The potential change is not limited to this pattern and is determined by a shape of the type judgement terminal formed in the test strip correspondingly to the type judgement electrode 172. For example, a test strip 184 in Fig. 15 may be designed to assume the potential change, i.e. the appropriate test strip set change from the high level when the test strip is inserted to the low level when the insertion is complete The concentration of the component is measured in the circuit constitution of Fig. 11. For instance, blood is dropped on the reaction reagent 182 of the test strip 181 and, a concentration of glucose in the blood is measured via the positive electrode 102 and negative electrode 103 of the measuring apparatus 171. The operation for measuring the concentration as above is not fundamentally different from the description of the first embodiment, the description of which is accordingly omitted.
According to the fourth embodiment, only when the test strip 181 having the measurable reaction reagent 182 is inserted in the measuring apparatus 171, is the component measured.
This prevents a test strip from being used for the wrong test.
In the foregoing embodiments, while each concentration measuring apparatus is adapted to identify the test strip conforming to each concentration measuring apparatus, the test strips cannot be used in common among the measuring apparatuses. For example, the test strip 115 of Fig. 2 is appropriate to the measuring apparatus 101 of Fig. 1, similarly, the test strip 141 of Fig. 5 to the measuring apparatus 131 of Fig. 4. Even when the test strip 141 of Fig. 5 is set to the measuring apparatus 101, the component measurement cannot be executed in the measuring apparatus 101. Similarly, even though the test strip 115 of Fig. 1 is set to the measuring apparatus 131, the measuring apparatus 131 cannot execute the component measurement. From this, the present invention in the embodiments can realize a biosensor system which prohibits test strips from being shared among different concentration measuring apparatuses.
Fig. 16 is a modified example of the concentration measuring apparatus 101 of Fig. 1. A
concentration measuring apparatus 201 may be constituted of the positive electrode 102, negative electrode 103, and type judgement electrode 104 arranged in this order orthogonal to the insertion direction I. A test strip 205 capable of measuring the component in the measuring apparatus 201 is shown in Fig. 17. The test strip 205 has a first terminal 206 for electrically connecting the positive electrode 102 and type judgement electrode 104 of the measuring apparatus 201. Moreover, a second terminal 207 is formed which is electrically connected to the negative electrode 103 of the measuring apparatus 201.
Even when the test strip 115 conforming to the measuring apparatus 101 is inserted in the measuring apparatus 201, the component measurement is impossible. Also, even when the test strip 205 matching the measuring apparatus 201 is inserted in the measuring apparatus 101, the component cannot be measured. That is because the positive electrode 102 and type judgement electrode 104 are not short circuited in any case. As above, the present invention can provide by changing constitutions the biosensor system wherein the test strips cannot be shared even among the measuring apparatuses of the same embodiment.

Basically the concentration measuring apparatus in each embodiment described hereinabove is capable of measuring one kind of component, e.g., glucose, and is adapted to execute the measurement of the concentration of glucose only when the test strip with the reaction reagent fit for the measurement of glucose is set thereto. However, the above concentration 5 measuring apparatuses in each embodiment and a concentration measuring apparatus according to a fifth embodiment to be described below are not limited to this model. For example, the measuring apparatus is devisable and may be set when shipped or before used so that it can measure a plurality of required kinds of components, and the concentration measurement is executed only when the corresponding test strips to the required components 10 are inserted.
In the foregoing description, the type judgement electrode and type judgement terminal are used to detect whether or not the test strip corresponding to the component to be measured by the measuring apparatus is set to the measuring apparatus. However, the technical idea of 15 using the type judgement electrode and type judgement terminal is not limited to the idea of the above-mentioned embodiments, which is utilizable, for example, to calibrate the measuring apparatus as in the following fifth embodiment. The calibration executed in the measuring apparatus includes at least compensation for an error in component concentration through the selection of a required calibration curve among a plurality of calibration curves, 20 and checking of the operation of the measuring apparatus based on whether or not a predetermined concentration value is displayed when the test strip adjusted beforehand to display the predetermined concentration value is set to the measuring apparatus. The fifth embodiment exemplifies the above selection of the calibration curve.

Fifth Embodiment As described in the beginning of the "Best Mode for Carrying Out the Invention", the enzyme included in the reaction reagent applied on the base material of the test strip corresponding to the component to be measured has a production error for each production lot.
For instance, when a liquid test sample containing glucose of a concentration of 100mg/dl is dropped to a glucose reaction reagent including an enzyme of a first production lot, a measuring apparatus displays 100mg/dl. On the other hand, when the same liquid test sample is dropped to a reaction reagent including an enzyme of a second production lot, the measuring apparatus displays 90mg/dl. An error is included in the measured values as above due to the production error of the enzyme itself Although a factor causing the largest error in the measured values is the production error of the enzyme, resistance values at the positive terminal, negative terminal, etc. formed on the base material of the test strip induce the error as well, because the conductive carbon paste which is printed to form the terminals is also not free from the production error.
For eliminating the above problem, conventionally, calibration curve information for compensating for an estimated error in measured concentration thereby displaying a true concentration is stored beforehand in the measuring apparatus as disclosed, e.g., in the Japanese Patent Laid-Open Publication No. 4-357452. A calibration test strip for selecting calibration curve information that can compensate for the production error of each production lot from a plurality of calibration curve information is prepared for every group of test strips having the same production lot. Since the large influential factor for the measurement error is the production error of the enzyme, the same production lot generally corresponds to a group of test strips to which the reaction reagent including the enzyme of the same production error is applied. Conventionally, a user when using the test strip of a different production lot should first set the calibration test strip to the measuring apparatus and then select the calibration curve information corresponding to the production lot of the test strip used. So long as test strips used are of the same production lot, it is enough. to select the calibration curve information once, and not necessary to select the information every time each test strip of the same production lot is used.
As described hereinabove, in the conventional concentration measuring apparatus, the user is required to pay attention to a change of the enzymes of the test strips namely, a change of the production lots. Unless the calibration curve information corresponding to the production error of the enzyme is selected, a large error is included in the measured values displayed at the measuring apparatus.
The fifth embodiment is devised to solve the problem, in which a function of selecting the calibration curve information is exerted by the type judgement electrode, type judgement terminal, and CPU on the basis of the technical concept of the use of the type judgement electrode and type judgement terminal described in the foregoing embodiments.
As will be described hereinbelow, the fifth embodiment is constituted to be a modification of the fourth embodiment, because as every component to be measured generally has ten or more kinds of calibration curve information, it is necessary that type judgement terminals of the test strip distinguish the ten or more kinds of calibration curve information with as a small count of the type judgement terminals as possible. However, the selection of the calibration curve information is enabled not only by the modified constitution of the fourth embodiment, but a modification of the above second or third embodiment can handle the selection in some cases if the calibration curve information to be distinguished comprises only several kinds or so.
The fifth embodiment is so constituted as to select the calibration curve information by the type judgement terminal formed in the test strip, the type judgement electrode and CPU of the measuring apparatus, and at the same time, judge the measurable component, similar to the first through fourth embodiments. The fifth embodiment is not restricted to this constitution and, may be adapted simply to select the calibration curve information.
A concentration measuring apparatus and a test strip for the concentration measuring apparatus according to the fifth embodiment will be explained with reference to Figs. 19 through 24. CPUs 258, 308 and 358 to be described hereinbelow are embodiments to exert a function of the "change judge device".
Fig. 19 indicates a concentration measuring apparatus 251 of an example of the fifth embodiment, and Fig. 20 is a test strip 271 to be set to the concentration measuring apparatus 251.
The concentration measuring apparatus 251 corresponds to a modification of the concentration measuring apparatus 171 of the fourth embodiment described with reference to Fig. 11, having the positive electrode 102, three type judgement electrodes 252, 253 and 254, and negative electrode 103 arranged orthogonal to the insertion direction I of the test strip 271. The positive electrode 102 is connected to the input of the amplifier 105 which has the output connected to the CPU 258 via the A/D converter 107. The negative electrode 103 is grounded. The type judgement electrodes 252-254 are connected to the CPU 258 via respective connecting lines 255-257. Generally, each voltage of +SV is applied via resistors to each of the connecting lines 255-257.
The CPU 258 is provided with a memory part 259 storing a plurality of calibration curve information for the compensation of the measurement error in concentration of the specific component included in the liquid test sample. Similar to the measuring apparatus of each embodiment described above, the CPU 258 carnes out control to measure the concentration only when the test strip 271 with the measurable reaction reagent is inserted in the measuring apparatus 251, and select and extract from the memory part 259 in accordance with the production lot of the test strip 271 set in the measuring apparatus 251 a predetermined calibration curve information that can compensate for the measurement error Although an operation of the CPU 258 will be discussed in detail later, basically, the CPU
258 detects potential change patterns generated at each of the type judgement electrodes 252, 253 and 254 after the test strip 271 is started to be inserted in the insertion direction I to the measuring apparatus 251 before the test strip 271 is completely set to the apparatus 251. That is, the appropriate test strip change as described in the fourth embodiment and also detects a "calibration curve information selection change'' to be described later. Based on the detected appropriate test snip set change, the CPU 258 judges whether or not the test strip having the reaction reagent to react with the specific component measurable by the measuring apparatus 251 is set to the apparatus 251. Moreover, based on the detected calibration curve information selection change, the CPU 258 selects a calibration curve information by which the error in the measured concentration by the set test strip can be calibrated.

The type judgement electrodes 252-254 can be divided to a first electrode and a second electrode. The first electrode generates the appropriate test strip set change from the high level to the low level and from the low level to the high level after the test strip is started to be inserted before the test strip is perfectly set in the measuring apparatus, and generates the 5 calibration curve information selection change. In the fifth embodiment, the type judgement electrodes 252 and 253 work as the first electrode. The low level potential corresponds to the grounding level in the embodiment and, the high level potential corresponds to +SV. The second electrode alternately generates the high and low level potentials in synchronization with the potential change at the first electrode so as to detect timings of the appropriate test 10 strip set change and the calibration curve information selection change of the first electrode.
The type judgement electrode 254 corresponds to the second electrode in the fifth embodiment.
Although the first electrode is comprised of two electrodes in the fifth embodiment, a count 15 of electrodes of the first electrode is not specifically restricted to this.
The test strip 271 of Fig. 20 is similar in structure to the conventional test strip 1 shown in Figs. 33 and 34. A reference numeral 272 corresponds to the reaction reagent, which hides the measuring electrode 5 and counter electrode 6 in the drawing. The measurable reaction 20 reagent is applied to the test strip 271.
The test strip 271 has a positive terminal 273 and a negative terminal 274 extended in the insertion direction I to be electrically connected to the positive electrode 102 and negative electrode 103 of the measuring apparatus 251 respectively. The electric connection between 25 the positive electrode 102 and positive terminal 273 and between the negative electrode 103 and negative terminal 274 is maintained while the test strip 271 moves in the I direction after started to be inserted to the measuring apparatus 251 before complete insertion. The test strip 271 is further equipped with type judgement terrnin rrls 275, 276 and 277 corresponding to the type judgement electrodes 252, 253 and 254 of the measuring apparatus 251. Two type judgement terminals 275-1 and 275-2 constituting the type judgement terminal 275 are formed discontinuously on a passage of the type judgement electrode 252, and moreover four type judgement terminals 276-1 through 276-4 constituting the type judgement terminal 276 are formed discontinuously on a passage of the type: j udgement electrode 253 so as to bring about the appropriate test strip set change and the calibration curve information selection change to the type judgement electrodes 252 and 253 during the movement of the test strip 271 along the direction I after started to be inserted to the measuring apparatus 251 before complete insertion. The type judgement terrt7inals 275 and 276 correspond to a part for generating potential change to the first electrode. The type judgi;ment terminals 275-1 and 275-2, and type judgement terminals 276-1 through 276-4 are connected to the negative terminal 274 via connecting lines. The connecting lines are electrically insulated from the type judgement electrodes 252-254 so as to prevent the electric connection between the type judgement electrodes 252-254 and the connecting lines consequent. to the movement of the type judgement electrodes 252-254.
In order to generate timings for the appropriate test strip change and the calibration curve information selection change to the type judgement electrode 25~~I during the movement of the test strip 271 in the insertion direction I after started to be inserted to the measuring apparatus 251 before complete insertion, two type judgement terminals 27~?-1 and 277-2 constituting the type judgement terminal 277 are formed discontinuously on ur passage of the type judgement electrode 254. The type judgement terminal 277 corresponds to a part for generating timings for the second electrode. In the embodiment, the type judgement terminals 277-1 and 277-2 are formed integrally with the negative terminal 274.
Meanwhile, a set completion detection terminal 278 is Iormed integrally with the negative terminal 274 in the test strip 271 so that the measuring apparatus 251 detects when the test strip 271 is completely set to the apparatus 251.
The above-described positive terminal 273, negative terminal 2 74, type judgement terminals 275-277 and set completion detection terminal 278 are formed by printing of a conductive material or the like, similar to the prior an. A formation method of the terminals will be described more in detail later.
Although six type judgement terminals 275 arid 276 are provided as the part for the potential change to the first electrode according to the fifth embodiment, a count of the type judgement terminals is not confined to this and can be determined by a count of kinds of calibration curve information to be selected and so on.
The concentration measuring apparatus 251 constituted as above operates in the following fashion.
In Fig. 20, at a time point immediately after the test strip 271 is inserted to the measuring apparatus 251 in the insertion direction I, the positive electrode 102, type judgement electrodes 252-254, and negative electrode 103 of the measuring apparatus 251 are placed at a position shown by a line 281. The positive electrode 102 is electrically connected to the positive terminal 273 of the test strip 271, the type judgement electrodes 253 and 254 are respectively electrically connected to the type judgement tercninsrls 276-1 and 277-1, and the negative electrode 103 is electrically connected to the negative terminal 274, whereas the type judgement electrode 252 without a corresponding terminal thereto has no electric connection. The type judgement terminals 275-I, 275-2 and 27fi-1 through 276-4 are electrically connected to the negative terminal 274, and the type judgement terminals 277-1 and 277-2 are integrally formed with the negative terminal 274. As a result, the grounded negative electrode 103 is electrically connected to the negative terminal 274, then the type judgement terminals 275-1, 275-2, 276-l, 27fi-2, 276-3, 276-4, 277-I and 277-2 are turned to the low level potential, that is, grounding potential in the embodiment via the negative terminal 274. At the time point 281 when the test stxip is started to be inserted, the type judgement electrodes 253, 254 and negative electrode 103 are thi; grounding potential, namely, the low level potential, and the connecting lines 256, 257 connected to the type judgement electrodes 253, 254 are the grounding potential, while the connecting line 255 connected to the type judgement electrode 252 is +5V, i.e., the high level potential.
In accordance with the further insertion of the test strip 271 to the measuring apparatus 251 along the insertion direction I, when the positive electrode 1072, type judgement electrodes 252, 253, 254, and negative electrode 103 are present at a position shown by a line 282, the positive electrode 102 keeps the connection to the positive terminal 273, the negative electrode 103 also maintains the connection to the negative terminal 274 and the type judgement electrodes 252, 253 are connected electrically to tlae type judgement terniinals 275-1, 275-2 respectively. While, the type judgement electrode 254 has no corresponding terminal thereto, and therefore is not electrically connected. At the position 282, therefore, the type judgement electrodes 252 and 253, arid negative electrode IU3 are the grounding potential, the connecting line 255 connected to the type judgement electrode 252 and connecting line 256 are the grounding potential and, the connecting line 257 connected to the type judgement electrode 254 is +SV, namely, the high level potential.
Similarly, when the test strip 271 is advanced in the insertion direction I to the measuring apparatus 251 and then the positive electrode 102, type judgement electrodes 252-254 and negative electrode 103 are present at a position shown by a line 283, the positive electrode 102 holds the connected state to the positive terminal 273 and the negative electrode 103 likewise holds the connection to the negative terminal 274, with the connecting line 255 brought to the high level potential and the connecting lines 256 and 257 changed to the grounding potential. Thereafter, when the test strip 271 is inserted in the set direction I to the measuring apparatus 251 thereby to locate the positive electrode 102, type judgement electrodes 252-254 and negative electrode 103 at a position shown by a line 284, the positive electrode 102 is maintained in the connected state to the positive terminal 273, the negative electrode 103 is still connected to the negative terminal 274, the connecting lines 255 and 256 become the grounding potential and the connecting line 257 is changed to the high level potential. With the positive electrode 102, type judgement electrodes 252-254 and negative electrode 103 present at a position shown by a line 285 when the test strip 271 is finally set to the measuring apparatus 251, each connected state of the positive electrode 102 to the positive terminal 273 and of the negative electrode 103. to the negative terminal 274 is retained, and the connecting lines 255-257 are all turned to the grounding potential.
In accordance with the movement of the test strip 271 after the test strip 271 is started to be inserted before the test strip 271 is completely inserted in the measuring apparatus 251, in other words, in accordance with the movement of the positive electrode 102, type judgement electrodes 252-254; and negative electrode 103 from the position 281 to the position 285, the CPU 258 of the measuring apparatus 251 detects the potential change at the type judgement electrodes 252-254, namely, connecting lines 255-257. More specifically, when the test strip 271 is completely inserted in the measuring apparatus 251 and when the CPU 258 detects that every connecting line 255-257 reaches the grounding potential, the CPU 258 judges that the 5 test strip 271 is inserted to a set completion position of the measuring apparatus 251. The connecting line 257 changes from the grounding potential -~ high level potential ~
grounding potential ~ high level potential to the grounding potential in accordance with the movement of the test strip 271 from a start position to the completion position. In other words, the grounding potential and high level potential are alternately repeated at the 10 connecting line 257. The CPU 258 detects the alternating potential change at the connecting line 257. Based on the alternating potential change, the CPU 258 obtains a detection timing of the appropriate test strip set change which is the potential change at the connecting lines 255, 256 and also checks whether or not the test strip 271 is normally set to the measuring apparatus 251. That is, only when the connecting line 257 becomes the high level potential 15 twice after the start position to the set completion position of the test strip 271; the CPU 258 judges that the test strip 271 is set normally to the measuring apparatus 251.
In other cases than the above, the CPU 258 judges that the test strip 271 moves in an opposite direction to the insertion direction I at least once, in other words, the test strip 271 returns, and shows, for example, an error display.
Synchronously with the potential change of the connecting line 257, the CPU
258 detects the appropriate test strip change which is developed at the connecting lines 255, 256.
Specifically, in the fifth embodiment, when the test strip 271 is. normally set to the measuring apparatus 251 from the start to the completion of the setting, the connecting line 255 changes from the high level potential ~ grounding potential -~ high level potential ~

grounding potential to the grounding potential, and the connecting line 256 changes from the grounding potential -~ grounding potential -~ grounding potential ~ grounding potential to the grounding potential. The CPU 258 recognizes a pattern of the potential change at each of the connecting lines 255 and 256 while the type judgement electrodes 252, 253 are moved to locate from the positions 281 through 284. In the present embodiment, since there are six type judgement terminals 275, 276 at positions 281 through 284, the potential change can be 26, namely 64 patterns at maximum. These 64 patterns of the potential change correspond to the calibration curve information and further in the embodiment, information of the specific component measurable by the set test strip 271, stored in the memory part 259.
In the fifth embodiment, the CPU 258 selects the information of the specific component, namely, information for the identification of the type of the test strip, on the basis of each potential of the connecting lines 255 256 immediately before the type judgement terminals 252, 253 are located at the set completion position 285, i.e., at the position 284, and selects the calibration curve information on the basis of the "calibration curve information selection change". The "calibration curve information selection change" is the potential change of the connecting lines 255, 256 while the type judgement terminals 252, 253 are moved from the positions 281 through 283. Accordingly, there are 24=16 patterns of the calibration curve information selection change for selecting the calibration curve information and 22=4 patterns of the potential change for selecting the information of the specific component in the fifth embodiment.
Based on the recognized pattern of the potential change, the CPU 258 selects and extracts from the memory part 259 the calibration curve information corresponding to the production lot of the set test information of the specific component test strip 271.

When the test strip 271 is set to the concentration measuring apparatus 251, the CPU 258 is turned into a measurable condition if the CPU 258 decides that the test strip 271 conforming to the specific component measurable by the measuring apparatus 251 is set based on the selected information indicative of the specific component, i.e., their identification of the type of test strip. And then the CPU 258 selects and extracts the calibration curve information corresponding to the production lot of the test strip 271. The concentration of, e.g. glucose in blood is measured via the positive electrode 102 and negative electrode 103 of the measuring apparatus when the blood is dropped onto the reaction reagent of the set test strip 271. The CPU 258 calibrates the concentration with the use of the selected calibration curve information in operating the concentration of the specific component and make the result displayed. Since the measurement operation for the concentration is carried out essentially similar to the manner as is described in the first embodiment, the description thereof will be omitted here.
In contrast, if the test strip 271 corresponding to a specific component is not measurable by the measuring apparatus 251 is set, the CPU 258 is not turned to the measurable state and displays, for example, an error display.
In the above-described fifth embodiment, only when the test strip 271 having the measurable reaction reagent in inserted in the measuring apparatus 251, can the measurement be executed Therefore, such an inconvenience can be prevented that a lactate test strip is set inadvertently to the measuring apparatus and a wrong result is obtained although glucose is to be measured.
Moreover, when the test strip 271 for the specific component is set, the concentration can be the calibrated with the use of the calibration curve information corresponding to the production lot of the test strip 271, thereby making it unnecessary for the user to pay attention to the production lot of the test strip and set the calibration test strip to select the calibration curve information. Thus, when a correct test strip having the measurable reaction reagent is inserted, the concentration of the component can be obtained without the calibration. The user is accordingly saved from the conventional trouble of using both the calibration test strip and the measurement test strip and then liberated from annoyance.
According to the fifth embodiment, as described hereinabove, there are two kinds of patterns in the appropriate test strip change which is the potential change at the connecting lines 255, 256, i.e. the potential change pattern for the calibration curve information selection change and the potential change pattern for selecting the information indicative of the specific component. However, the present invention is not limited to this. For example, in the event that the specific component measurable by the measuring apparatus is already known and the test strip corresponding to the specific component is set at all times, the potential change pattern for selecting the information of the specific component is not required, and therefore, the pattern in the appropriate test strip change can be totally utilized for the pattern of the calibration curve information selection change. To the contrary, other kinds of the potential change may be added to the above to form three or more kinds of patterns.
The concentration measuring apparatus and test strip are not limited to the embodiment shown in Figs. 19 and 20, for example, may be modified into forms shown in Figs. 21 through 24 which will be now be depicted below.
The potential change at the two connecting lines 255, 256 is used to select the calibration curve information and the specific component information in the above concentration measuring apparatus 251. On the other hand, according to a concentration measuring apparatus 301 of Fig. 21, a potential change at one connecting line 306 among three type judgement electrodes 302-304 is detected by a CPU 308 and this detected information is utilized at least for the selection of the calibration curve information. Both connecting lines 305, 307 are connected to each +SV power source via respective a lOkS2 resistor. A
constitution of the measuring apparatus 301 in other points is not varied from that of the aforementioned measuring apparatus 251.
A fundamental concept related to formation of terminals on a test strip 321 to be inserted in the measuring apparatus 301 is similar to that of the test strip 271. However, a difference is that the test strip 321 is provided with one type judgement terminal 325 to the type judgement electrodes 302 and 303 although the test strip 271 has separate type judgement terminals 275 and 276 corresponding to the type judgement electrodes 252 and 253. Since the one type judgement terminal 325 is provided correspondingly to the type judgement electrodes 302 and 303, in the concentration measuring apparatus 301, the type judgement terminal 325 is adapted to be positioned at six points along the insertion direction I so as to obtain the above 64 patterns of the appropriate test strip change, similar to the measuring apparatus 251.
Needless to say, a count of the type judgement terminal 325 is not limited to the above six points and can be determined in accordance with a count of the patterns of the appropriate test strip change.
The operation of the measuring apparatus 301 of the above constitution will be described.
At a start time point when the test strip 321 is started to be fitted to the measuring apparatus 301, the positive electrode 102, three type judgement electrodes 302-304, and negative electrode 103 are located at a position shown by a line 331. The positive electrode 102 is electrically connected to a positive terminal 323 of the test strip :.321, the type judgement electrodes 302, 303 are electrically connected to the type judgement terminal 325, the type judgement electrode 304 is electrically connected to a type judgement terminal 327 and, the negative electrode 103 is electrically connected to a negative terminal 324, T'he type 5 judgement terminal 327 of the test strip 321 generates the timing, similar to the type judgement terminal 277 of the test strip 271. In accordance with the movement of the test strip 321 in the insertion direction I, the type judgement terminal 327 generates the alternating potential change of the grounding potential and high bevel potential to the connecting line 307 connected to the type judgement electrode 304. In the measuring 10 apparatus 301, the CPU 308 judges that the test strip 321 is uom~ally inserted in the measuring apparatus 301 solely when the connecting line 3U 7 becomes the high level potential three times after the start to completion of the setting oi'the test strip 321 and shows, e.g., an error display in other cases except the above.
15 When the type judgement electrodes 302 and 303 are electrically connected by the type judgement terminal 325, the source voltage is impressed to the connecting line 306 connected to the type judgement electrode 303 via the IOkSZ resistor and connecting line 305, so that the connecting line 306 becomes the high level potential. When the test strip 321 moves further in the insertion direction I and if the type judgement terminal 325 is absent, e.g., as when the 20 type judgement electrodes 302 and 303 are located at a position shown by a line 333, the type judgement electrodes 302 and 303 are not electrically connected with each other. In this case, the connecting line 306 is grounded via the 100kS2 resistor and consequently turned to the low level potential. In the present example, in accordance with the movement of the test strip 321 from the start position to a set completion position where the positive electrode 102, 25 three type judgement electrodes 302-304, and negative electrode 103 are on a line 337, the connecting line 306 shows the potential change from the high level potential -> high level potential ~ low level potential ~ high level potential -~ high level potential ~ high level potential to the low level potential. Depending on a presence/absence of the type judgement terminal 325, the potential change can be given rise to the connecting line 306 while the test strip 321 is moved from the start position to the set completion position. The detects the potential change pattern at the connecting line 306, and then selects and extracts, e.g., the calibration curve information stored beforehand in a memory part 309 corresponding to the potential change pattern of the connecting line 306. The measuring apparatus 301 operates in the same way in other points as the measuring apparatus 251, the description of which will be saved here.
Refernng to Fig. 23, in a concentration measuring apparatus 351, a potential change at one connecting line 356 is detected, similar to the measuring apparatus 301, thereby to select, e.g., the calibration curve information. A constitution for generating the potential change to the connecting line 356 is different in comparison with the measuring apparatus 251.
Specifically, the measuring apparatus 351 has three type judgement electrodes 352-354, connecting lines 355-357 connected to the type judgement. electrodes 352-354, a CPU 358, and a memory part 359 storing the calibration curve information or the like.
Each +SV power source is connected via respective resistors to the connecting lines 355-357.
The measuring apparatus 351 is additionally provided with a grounding electrode 360 adjacent to the type judgement electrode 353 of the connecting line 356 generating a potential change detected by the CPU 358. When the CPU 358 detects that the type judgement electrode 352 is electrically connected to a set completion detection terminal 378 to be described later, the CPU 358 recognizes a set completion of a test strip 371 to the apparatus 351.

In the meantime, the test strip 371 to be set to the measuring apparatus 351 has the positive terminal 323, negative terminal 324, and type judgement terminal 375, etc., similar to the test strip 321. The test strip 371 also includes the insertion completion detection terminal 378 integrally formed with the negative terminal 324. The insertion completion detection terminal 378 detects when the test strip 371 is completely inserted to the measuring apparatus 351. The detection terminal 378 is formed to be electrically connected to the type judgement electrode 352 when the type judgement electrode 352 is located at the insertion completion position denoted by 387. The constitution of the test strip 371 in other points is the same as that of the test strip 321.
An operation of the thus-constituted measuring apparatus 351 will be described hereinbelow.
Since the operation is fundamentally similar to that of the measuring apparatus 301, only a difference between the apparatus 351 and the apparatus 301 will be depicted.
That is, when the test strip 371 is started to be inserted into the measuring apparatus 351, the type judgement electrode 353 and grounding electrode 360 are located at a position shown by a line 381 and electrically connected to the type judgement terminal 375.
Since the electric connection of the type judgement electrode 353 is electrically connected to the grounding electrode 360 via the type judgement terminal 375, a potential change of the connecting line 356 detected by the CPU 358 becomes the grounding potential. When the test strip 371 is further inserted in the insertion direction I and the type judgement electrode 353 and grounding electrode 360 are located at a position shown by a line 383, since the test strip 371 has no type judgement terminal, the connecting line 356 becomes the high level potential of +SV.

According to the embodiment as is described hereinabove, with the movement of the test strip 371 before the positive electrode 102, three type judgement electrodes 3S2-354, grounding electrode 360, and negative electrode lU3 reach the position shown by the line 387 after the test strip 371 is started to be inserted, the connecting line 3S6 shows the potential change from the grounding potential --~ grounding potential --~ high level potential -~
grounding potential ~ grounding potential -,~ grounding potential to the grounding potential.
Therefore, the connecting line 3S6 undergoes the potential change in accordance with the movement of the test strip 37l after the start to the cc7mpletion ol~the setting, depending on presence/absence of the type judgement terminal 375. The CPU 3S8 detects the potential change pattern of the connecting line 356, and then selects grad extracts, e.g., the calibration curve information stored in the memory part 3S9 beforehand correspondingly to the potential change pattern of the connecting line 356. The measuring apparatus 351 operates in the same manner in other points as the measuring apparatus '?S ( described earlier, and therefore the description thereof will be omitted.

A method for forming the positive terminal, type judgement terminals, negative terminal, and set completion detection terminal formed in the toss strip of the fifth embodiment, particularly, a method for forming the type judgement terminals will be explained below.
As described before, the test strip inevitably includes the measurement error for every production lot and the large factor for the measurement error is the production error of the enzyme in the reaction reagent 272, 322 or :372. Thus, the method for forming the judge elements to be described hereinbelow is a method to form the judge elements base~.l on the production error of the enzyme. The test strip 271 is taken as an example in the following description, and the following description is directed to a case of forming the calibration curve information selection pattern to the type judgement terminals 275-277 of the test strip.
There are generally two methods for forming the positive terminal, type judgement terminals, etc. According to a first method, after the production error of the reaction reagent, particularly, of the enzyme is confirmed, the type judgement terminal is formed so that at least the calibration curve information selection change is brought about to the connecting line. According to a second method, a type judgement terminal without a pattern is formed preliminarily along the insertion direction I and, after the production error of especially the enzyme is confirmed, an insulating substance is applied onto the type judgement terminal without the pattern so that at least the calibration curve information selection change is brought about to the connecting line.
The aforementioned first method will be described with references to Figs. 25 through 28.
1 S As shown in Fig. 25, the measuring electrode, counter electrode; and connecting lines connected to these electrodes are formed on the base material of a sample test strip 271 to determine the calibration curve information An insulating layer is formed with an insulating paste or the like except a part of the measuring electrode and counter electrode, as indicated by slanted lines in Fig. 26, and thereafter the reaction reagent 272 is applied on the measuring electrode and counter electrode. The slanted lines in Figs. 26-28 are not a hatching representing a cross section. Then, in Fig. 27, a standard solution containing a specific component which reacts to the reaction reagent 272 and a concentration of which is known is dropped to the reaction reagent 272, and a voltage is applied to a part of the reaction reagent 272. Then a concentration, i.e. a current value, is measured. A measurement error of the reaction reagent 272 is obtained on the basis of the measured concentration and the known concentration. In Fig. 28, type judgement terminals 275, 276 and positive terminal 273, etc.
are formed of conductive material so that the calibration curve information selection change corresponding to the calibration curve information compensating for the above measurement error is brought about with the type judgement terminals 275, 276 and positive terminal 273, etc.
In the foregoing description, the test strip is the sample for determining the calibration curve information. In a case of the test strip 271 for sale to which a reaction reagent including an enzyme of the same production lot as the enzyme of the reaction reagent applied to the 10 sample element is applied, a type of the conductive material forming the type judgement terminal 275, etc. should be selected in accordance with an application timing of the reaction reagent onto the base material. Namely, in general, the enzyme included in the reaction reagent 272 is weak to heat and an activity of the enzyme is decreased or the enzyme becomes inactive once a temperature not lower than about SO°C acts the enzyme, whereby 15 the test strip 271 is inoperative. Thus, in the case where the test strip 271 is produced after the calibration curve information corresponding to the production lot is determined, and if the reaction reagent 272 is applied onto the base material before the type judgement terminal 275, etc. are formed, a conductive material of a type cured at normal temperatures should be used for the type judgement terminal 275, etc., as in Fig. 28. The conductive material of the 20 above type is, for example, a conductive adhesive containing silver and an epoxy resin binder such as "ELECTRODAG5820" (trade name by Acheson (Japan) Ltd.) or a conductive adhesive containing nickel and a thermoplastic binder such as "SS24306" (trade name by Acheson (Japan) Ltd.), etc.

Meanwhile, when the reaction reagent 272 is applied on the base material after the type judgement terminal 275, etc. are formed, the conductive material of the above-described type, i.e., curing at normal temperatures is not necessary and a conventionally used thermosetting conductive material requiring heating at approximately 130-150°C can be employed.
The second method will be described with reference to Figs. 29-32. In Fig. 29, on the base material of the sample test strip 271 used for determining the calibration curve information are formed the measuring electrode, the counter electrode, the connecting lines connected to these electrodes, the positive terminal 273, the negative terminal 274, the set completion detection terminal 278, and type judgement terminals 401, 402 without the pattern. Similar to the description with reference to Fig. 26, after an insulating layer is formed except the part of the measuring electrode and counter electrode, the reaction reagent 272 is applied, as indicated by slanted lines in Fig. 30. The slanted lines in Figs. 30-32 are not a hatching to express cross sections. In Fig. 31, the standard solution is dropped to the reaction reagent 272, and a voltage is applied to the part of the reaction reagent 272 via the positive terminal 273 and negative terminal 274. Then, a concentration of the standard solution i.e., a current is measured. Based on the measured concentration and known concentration, a measurement error of the reaction reagent 272 is obtained. In Fig. 32 then, insulating pastes 405, 406, etc.
are applied as indicated by slanted lines onto the type judgement terminals 401, 402 without the pattern so that the calibration curve information capable of compensating for the above measurement error can be selected, thereby to form a pattern for selecting the calibration curve information and obtain type judgement terminals 275, 276. As a way to form the pattern for selecting the calibration curve information to the type judgement terminals 401, 402 without the pattern, cutting or the like process may be perfoz-tned to the type judgement terminals 401, 402, in place of applying the insulating pastes 40~, 406 of the type cured at normal temperatures.
The insulating pastes 405, 406 of the above type are, e.g., an insulating ink containing a polyurethane PV series resin binder such as "JEF-226C" (trade name by Acheson (Japan) Ltd.) or an insulating ink containing a polyester resin binder such as "JEH-116G" (trade name by Acheson (Japan) Ltd.), etc.
As mentioned earlier, the insulating paste of the thermosetting type; can be used depending on the application timing of the reaction reagent 272 to tine test strip 271.
According to the second method as above, since the positive terminal 273 and negative terminal 274 are used when the concentration of the standard solution is measured as in Fig. 31, the concentration can be measured with the production error of the conductive carbon paste as the material for the positive terminal 273 and negative tcnninal 274 included, unlike the first method. Therefore, the concentration of the specific component can be measured with higher accuracy than by the first method.

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art.
Such changes and modifications are to be understood as included within the scope of the present invention.

Claims

1. ~A concentration measuring apparatus for measuring the concentration of a specific component in a liquid sample included in a test strip, the test strip being inserted in the concentration measuring apparatus, the test strip including a reaction reagent which is to react with the liquid sample, the test strip further including a positive terminal and a negative terminal, the concentration measuring apparatus comprising:
a positive electrode and a negative electrode for electrically detecting the concentration of the specific component in the liquid sample, the positive electrode being connected to the positive terminal of the test strip, the negative electrode being connected to the negative terminal of the test strip; and a type judgement electrode for judging a type of the reaction reagent on the inserted test strip, the type judgement electrode being separate from the positive electrode and the negative electrode.

2. ~The concentration measuring apparatus of Claim 1, further comprising:
a first identification device for feeding information corresponding to the test strip based on a fact that the type judgement electrode is connected with the positive electrode only when the test strip capable of measuring the specific component is inserted in the concentration measuring apparatus; and a second identification device for identifying the test strip based on the information fed from the first identification device.

3. ~The concentration measuring apparatus of Claim 1, further comprising:
at least one positive electrode switch for connecting or disconnecting the type judgement electrode and positive electrode;
at least one negative electrode switch for connecting or disconnecting the type judgement electrode and negative electrode; and an identification device for identifying that the test strip capable of measuring the specific component is inserted in the concentration measuring apparatus on the basis of information obtained from a detecting part of the positive electrode consequent to turning ON/OFF of each of the positive and negative electrode switches.

4. ~A test strip to be inserted in the concentration measuring apparatus of Claim 2, the test trip comprising:
a type judgement terminal which is to be electrically connected to the type judgement electrode and the positive electrode, thereby letting the first identification device of the concentration measuring apparatus send out the information corresponding to the test strip.

5. ~The concentration measuring apparatus of Claim 1, further comprising:
a potential judge device connected to the type judgement electrode which judges whether or not the type judgement electrode reaches an appropriate test strip potential which is a potential generated at the type judgement electrode when the test strip capable of measuring the specific component is inserted in the concentration measuring apparatus.

6. ~The concentration measuring apparatus of Claim 5, wherein the type judgement electrode comprises:

at least two high level electrodes set at a high level potential, and a grounding electrode set at a low level potential, so that at least one of the possible combinations of potentials at the two high level electrodes and the grounding electrode corresponds to the appropriate test strip potential.

7. ~A test strip to be inserted in the concentration measuring apparatus of Claim 5, the test strip comprising:
a type judgement terminal which is to be electrically connected to the type judgement electrode and allows the potential judge device to judge that the potential at the type judgement electrode is the appropriate test strip potential.

8. ~A test strip to be inserted in the concentration measuring apparatus of Claim 6, the test strip comprising:
at least two type judgement terminals to be electrically connected at least to the three type judgement electrodes, enabling the potential judge device to judge the appropriate test strip potential through a combination of connections of the type judgement electrodes and the type judgement terminals.

9. ~The test strip of Claim 8, wherein the type judgement comprises:
a first terminal for electrically connecting one of the high level electrodes and the grounding electrode; and a second terminal to be electrically connected to the remaining high level electrode.

10. The concentration measuring apparatus of Claim 1, further comprising:
a change judge device connected to the type judgement electrode which judges whether or not a potential change at the type judgement electrode corresponds to an appropriate test strip change which is a change generated at the type judgement electrode when the test strip capable of measuring the specific component is inserted in the concentration measuring apparatus.

11. The concentration measuring apparatus of claim 10, wherein the type judgement electrode is set at a high level potential.

12. A test strip to be inserted in the concentration measuring apparatus of Claim 10, the test strip comprising:
a type judgement terminal to be electrically connected to the type judgement electrode and allows the change judge device to judge that the potential change at the type judgement electrode corresponds to the appropriate test strip change.

13. The test strip of Claim 12, wherein the type judgement terminal is electrically connected to the positive terminal or negative terminal, and is electrically connected to the type judgement electrode of the concentration measuring apparatus either when the test strip is started to be inserted in the concentration measuring apparatus or when the test strip is completely inserted in the concentration measuring apparatus, and the type judgement terminal brings about the appropriate test strip change to the type judgement electrode from the high level to low level or from the low level to high level after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion.

14. A test strip to be set to the concentration measuring apparatus of Claim 11, the test strip comprising:
a type judgement terminal to be electrically connected to the type judgement electrode and allows the change judge device to judge that the potential change at the type judgement electrode is the appropriate test strip change.

15. The test strip of Claim 14, wherein the type judgement terminal is electrically connected to the negative terminal, and is electrically connected to the type judgement electrode of the concentration measuring apparatus when the test strip is started to be inserted in the concentration measuring apparatus, and brings about the appropriate test strip change to the type judgement electrode from the low level to high level after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion.

16. A biosensor system comprising:
a first concentration measuring apparatus comprising the concentration measuring apparatus of Claim 2 wherein the positive electrode, the type judgement electrode, and the negative electrode are arranged in this order orthogonal to an insertion direction of a test strip;
a first test strip comprising the test strip of Claim 4 to be inserted in the first concentration measuring apparatus which includes a first terminal to be electrically connected to the positive electrode and the type judgement electrode, and a second terminal to be electrically connected to the negative electrode;
a second concentration measuring apparatus comprising the concentration measuring apparatus of Claim 2 wherein the positive electrode, the negative electrode, and the type judgement electrode are arranged in this order orthogonal to the insertion direction; and a second test strip comprising the test strip of Claim 4 to be inserted in the second concentration measuring apparatus which includes a first terminal to be electrically connected to the positive electrode and type judgement electrode and a second terminal to be electrically connected to the negative electrode, wherein said biosensor system is so constituted that a concentration of the specific component cannot be measured if the first test strip is inserted in the second concentration measuring apparatus, and if the second test strip is inserted in the first concentration measuring apparatus.

17. The concentration measuring apparatus of Claim 10 or 11, wherein the change judge device:
stores a plurality of calibration curve information for compensating for an error in concentration measurement of the specific component in the liquid test sample;
detects a calibration curve information selection change at the type judgement electrode so as to select a required calibration curve information among the plurality of calibration curve information in place of judging the presence/absence of the appropriate test strip change at the type judgement electrode when the concentration measuring apparatus can measure the concentration of only one specific component and tire test strip having a reaction reagent which is to react to the specific component and capable of measuring the concentration of the specific component where inserted in the concentration measuring apparatus; and compensates for the error based on the calibration curve information selected in accordance with the detected calibration curve information selection change.

18. The concentration measuring apparatus of Claim 10 or 11, wherein the change judge device:
stores a plurality of calibration curve information for compensating for an error in concentration measurement of the specific component in the liquid test sample;
selects a required calibration curve information among the plurality of calibration curve information on the basis of a calibration curve information selection change included in the appropriate test strip change at the type judgement electrode as well as judges a type of the test strip on the basis of the appropriate test strip change at the type judgement electrode, and compensates for the error based on the selected calibration curve information.

19. The concentration measuring apparatus of Claim 18, wherein the change judge device stores the plurality of calibration curve information for every specific component corresponding to the type of the test strip.

20. The concentration measuring apparatus of Claim 18 or 19, wherein the type judgement electrode includes:
a first electrode which exhibits the appropriate test strip change from the high level to low level and from the low level to the high level after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion, and the calibration curve information selection change; and a second electrode which alternately generates the high level potential and low level potential synchronously with the potential change at the first electrode so as to detect a timing of the potential change of the first electrode after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion.

21. The concentration measuring apparatus of any one of Claims 17 to 20, wherein the error in concentration measurement results from a reaction error of the liquid test sample caused by a production error for every production lot of the reaction reagent of the test strip.

22. A test strip to be set to the concentration measuring apparatus of Claim 10 or 11, wherein the change judge device:

stores a plurality of calibration curve information far compensating for an error in concentration measurement of the specific component io the liquid test sample;

detects a calibration curve information selection change at the type judgement electrode so as to select a required calibration curve information among the plurality of calibration curve information in place of judging the presence/absence of the appropriate test strip change at the type judgement electrode when the concentration measuring apparatus can measure the concentration of only one specific component and the test strip having a reaction reagent which is to react to the specific component and capable of measuring the concentration of the specific component when inserted in the concentration measuring apparatus; and compensates for the error based on the calibration curve information selected in accordance with the detected calibration curve information selection change, said test strip comprising a type judgement terminal to be electrically connected to the type judgement electrode and allowing the change judge device to detect the calibration curve information selection change for selecting the required calibration curve information among the plurality of calibration curve information on the basis of the potential at the type judgement electrode.

23. A test strip to be set to the concentration measuring apparatus of Claim 10 or 11, wherein the change judge device:

stores a plurality of calibration curve information for compensating for an error in concentration measurement of the specific component in the liquid test sample;

selects a required calibration curve information among the plurality of calibration curve information on the basis of a calibration curve information selection change included in the appropriate test strip change at the type judgement electrode as well as judges a type of the test strip on the basis of the appropriate test strip change at the type judgement electrode, and compensates for the error based on the selected calibration curve information, said test strip comprising a type judgement terminal to be electrically connected to the type judgement electrode and allowing the change judge device to judge that the potential change at the type judgement electrode is the appropriate test strip change for judging the type of the test strip and also allowing the change judge device to detect the calibration curve selection information change for selecting the required calibration curve information among the plurality of calibration curve information.

24. ~The test strip of Claim 22, wherein the type judgement terminal comprises:

a potential change part which makes a first electrode included in the type judgement electrode of the concentration measuring apparatus represent the calibration curve information selection change from the high level potential to low level potential and from the low level potential to high level potential after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion;and a timing generation part which makes a second electrode included in the type judgement electrode of the concentration measuring apparatus alternately generate the high level potential and low level potential synchronously with the potential change brought about to the first electrode after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion.

25. The test strip of Claim 24, further comprising:

an insertion completion detection terminal to be electrically connected to the positive electrode or the negative electrode of the concentration measuring apparatus when the test strip is completely inserted in the concentration measuring apparatus,so that the completion of the insertion is detected with the concentration measuring apparatus.

26. The test strip of Claim 23, wherein the type judgement terminal comprises:

a potential change part which makes a first electrode included in the type judgement electrode of the concentration measuring apparatus represent the appropriate test strip change and the calibration curve information selection change from the high level to low level and from the low level to high level after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion; and a timing generation part which makes a second electrode included in the type judgement electrode of the concentration measuring apparatus alternately generate the high level potential and the low level potential synchronously with the potential change brought about to the first electrode after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion.

27. The test strip of Claim 26, further comprising:

an insertion completion detection terminal to be electrically connected to the positive electrode or negative electrode of the concentration measuring apparatus when the test strip is completely inserted in the concentration measuring apparatus, so that the insertion completion detection terminal makes the concentration measuring apparatus detect the completion of the insertion.
'

28. The test strip of any one of Claims 24 to 27, wherein the insertion completion detection part and the timing generation part are electrically connected to the negative terminal of the test strip.

29. The concentration measuring apparatus of any one of Claims 1,2,3,5,6,10, 11, 18, 19,20,and 21, which measures a concentration of the specific component in the liquid test sample detectable by the reaction reagent of the test strip, correspondingly to the test strip inserted in the concentration measuring apparatus.

30. The concentration measuring apparatus of any one of Claims 1,2,3,5,6,10,11,18, 19,20, and 21, which measures a concentration of the specific component in the liquid test sample which is measurable with the concentration measuring apparatus only when the test strip having the reaction reagent which is to react to the specific component in the liquid test sample is inserted in the concentration measuring apparatus.

31. A method for manufacturing the test strip to be set to the concentration measuring apparatus of Claim 10 or 11, wherein the change judge device:

stores a plurality of calibration curve information for compensating for an error in concentration measurement of the specific component in the liquid test sample;

detects a calibration curve information selection change at the type judgement electrode so as to select a required calibration curve information among the plurality of calibration curve information in place of judging the presence/absence of the appropriate test strip change at the type judgement electrode when the concentration measuring apparatus can measure the concentration of only one specific component and the test strip having a reaction reagent which is to react to the specific component and capable of measuring the concentration of the specific component when inserted in the concentration measuring apparatus; and compensates for the error based on the calibration curve information selected in accordance with the detected calibration curve information selection change, said test strip comprising a type judgement terminal to be electrically connected to the type judgement electrode and allowing the change judge device to detect the calibration curve information selection change for selecting the required calibration curve information among the plurality of calibration curve information on the basis of the potential at the type judgement electrode, said method comprising the steps of:

applying the reaction reagent on the base material of the test strip;

dropping a standard solution having the specific component of which a concentration is known to the applied reaction reagent; and selecting the calibration curve information compensating for an error between a detected concentration based on, the reaction and the known concentration of the specific component; and forming the type judgement terminal so that the calibration curve information selection change indicating at least the selected calibration curve information is generated at the type judgement terminal.

32. A method for manufacturing the test strip to be set to the concentration measuring apparatus of Claim 10 or 11, wherein the change judge device:

stores a plurality of calibration curve information for compensating for an error in concentration measurement of the specific component in the liquid test sample;

selects a required calibration curve information among the plurality of calibration curve information on the basis of a calibration curve information selection change included in the appropriate test strip change at the type judgement electrode as well as judges a type of the test strip on the basis of the appropriate test strip change at the type judgement electrode, and compensates for the error based on the selected calibration curve information, said test strip comprising a type judgement terminal to be electrically connected to the type judgement electrode and allowing the change judge device to judge that the potential change at the type judgement electrode is the appropriate test strip change for judging the type of the test strip and also allowing the change judge device to detect the calibration curve selection information change for selecting the required calibration curve information among the plurality of calibration curve information, said method comprising the steps of:
applying the reaction reagent on the base material of the test strip;
dropping a standard solution having the specific component of which a concentration is known to the applied reaction reagent; and selecting the calibration curve information compensating for an error between a detected concentration based on, the reaction and the known concentration of the specific component; and forming the type judgement terminal so that the calibration curve information selection change indicating at least the selected calibration curve information is generated at the type judgement terminal.

33. The method of Claim 31, wherein the type judgement terminal of the test strip comprises:
a potential change part which makes a first electrode included in the type judgement electrode of the concentration measuring apparatus represent the calibration curve information selection change from the high level potential to low level potential and from the low level potential to high level potential after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion; and a timing generation part which makes a second electrode included in the type judgement electrode of the concentration measuring apparatus alternately generate the high level potential and low level potential synchronously with the potential change brought about to the first electrode after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion.

34. The method of Claim 33, wherein the test strip further comprises:
an insertion completion detection terminal to be electrically connected to the positive electrode or the negative electrode of the concentration measuring apparatus when the test strip is completely inserted in the concentration measuring apparatus, so that the completion of the insertion is detected with the concentration measuring apparatus.

35. The method of Claim 32, wherein the type judgement terminal of the test strip comprises:
a potential change part which makes a first electrode included in the type judgement electrode of the concentration measuring apparatus represent the appropriate test strip change and the calibration curve information selection change from the high level to low level and from the low level to high level after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion; and a timing generation part which makes a second electrode included in the type judgement electrode of the concentration measuring apparatus alternately generate t:he high level potential and the low level potential synchronously with the potential change brought about to the first electrode after the test strip is started to be inserted in the concentration measuring apparatus before complete insertion.

36. The method of Claim 35, wherein the test strip further comprises:
an insertion completion detection terminal to be electrically connected to the positive electrode or negative electrode of the concentration measuring apparatus when the test strip is completely inserted in the concentration measuring apparatus, so that the insertion completion detection terminal makes the concentration measuring apparatus detect the completion of the insertion.

37. The method of any one of Claims 33 to 36, wherein the insertion completion detection part and the timing generation part of the test strip are electrically connected to the negative terminal of the test strip.

38. The method of any one of Claims 31 to 37, wherein the type judgement terminal of the test strip is formed on the base material of the test strip after the calibration curve information is selected so that the calibration curve information selection change indicating the selected calibration curve information is generated at the type judgement terminal.

39. The method of any one of Claims 31 to 37, wherein the type judgement terminal of the test strip is formed in a process of preliminarily forming a patternless type judgement terminal not showing the calibration curve information selection change on the base material of the test strip, and then forming a calibration curve information selection change pattern to the patternless type judgement terminal after the calibration curve information is selected so that the calibration curve information selection change indicating the selected calibration curve information is generated at the patternless type judgement terminal.