US2779232A - Blood counting method - Google Patents

Description

Jan. 29, 1957 F. R. SMALL BLOOD COUNTING METHOD Filed April 9, 1953 INVENTOR ffQ/7%R QYJZZQZZ ATTORNEY United States Patent BLOOD COUNTING METHOD Frank R. Small, Bartlesville, Okla.

Application April 9, 1953, Serial No. 347,745 2 Claims. (01. 88-14) I This invention relates to an improved method for the counting of microscopic bodies in a suspending liquid me-,

dium whose density is greater than or less than the'density of the microscopic bodies to be counted. More specifically, the invention comprises an improved method for the passage successively and individually ofmicroscopic bodies to be counted past a predetermined point and through a static suspending liquid medium.

In the patent to J an Kielland, No. 2,369,577, patented February 13, 1945, for Method and Apparatus for Counting Blood Corpuscles, there is disclosed a method for counting blood corpuscles in which a sample of blood is diluted in a dilution liquid, and thereafter the dilution liquid with the suspended corpuscles are caused to pass through a confined spaced and the blood corpu'scles counted. The primary object of the present invention is to provide an improvement over the method and apparatus disclosed in the aforesaid patent.

In accordance with the present invention, a sample of blood is diluted using one of the various diluting fluids common to the laboratory, such as Haymes diluting fluid for the diluting of red blood cells, Bethells diluting fluid for the diluting of red blood cells, 3.00 percent solution of acetic acid for the diluting of white blood cells, Rees- Ecker diluting fluid for the diluting of platelets, this dilution being fixed and constant, or the blood may be used whole for the counting of red blood cells by the use of a solid anticoagulant such as potassium oxalate or sodium oxalate, though the diluting fluid method is much preferred for accuracy and flexibility over the solid anticoagulant method. The method of diluting and the mechanical procedure and apparatus used in the diluting do not effect the present inventive concept. The important feature of the present invention is the use of a static medium of different density than the density of the'microscopic bodies being counted.

In a preferred manner, blood is taken by first selecting one of the various areas commonly used for taking blood specimens, such as finger, toe, ear lobe, or vein, cleansing area with alcohol and ether, puncturing area and allowing a specimen of blood to flow forth freely, or be withdrawn if a venipuncture method is used. A pipette is used to collect a definite volume of blood by drawing the blood up to a designated point on the pipette and the dilution is completed by addition of one of the various diluting fluids, which of course is chosen according to the test to be run, i. e., diluting fluid for a red blood count destroys components other than red blood cells, and vice versa. the dilution made the pipette is agitated in order to thoroughly distribute all contents in the dilution. This gives a homogeneous mixture of the microscopic bodies to be counted within the diluting fluid. The agitation can be done manually or by use of a shaker common to the laboratory.

The diluted specimen is introduced into a channeled tube having a counting point marked thereon, and the channeled tube placed in a substantially vertical position, or into a stationary channeled tube fixed in a substantially vertical position having a counting point marked thereon. The specimen dilution is static and at rest, that is, the fluid portion of the medium is not in movement, other than by molecular bombardment and slight current set up by movement'of microscopic bodies of greater or less density suspended in the fluid medium. Red blood cells, white blood cells, platelets, and other components of the blood component or object passes the counting point, it may be counted manually with the aid of a microscope, or by use of a photoelectric system or by a cathode ray operating on the photoelectric principle. It is recognized that it would be possible to magnify the passage of these components to such a size as to be recognizable to the naked eye.

The nature and advantages of the invention will be more readily understood from the following description, taken in connection with the accompanying drawing forming part hereof, in which:

Figure l is a diagrammatic view of an apparatus having a channeled tube, light source, lens, and a photoelectric counting means associated with the counting point of the channeled tube.

Figure 2 is avertical sectional view of one form of counting channel.

Figure 3 is a vertical sectional view of a channeled tube which may be used with the present invention.

Figures 4 and 5 are similar views showing modified forms of channeled tubes,

Figure 6 is a cross-sectional view of the channeled tube at the counting point and taken on the line 6-6 of Figure 3.

Figures 7, 8 and 9 are similar views showing modified forms of the cross-sectional area of the tube at the countblood corpuscles which are to be counted to pass individ- With ually and successively through the passage past the counting point. As illustrated in Figures 1, 2 and 3, the dimensions of the channeled tube 10 are substantially uniform throughout its length. V g g "In Figure 4, the interior passage of the tube is shown as being tapered and the counting point 13a is located at the point of smallest diameter.

In Figure 5, the interior passage of the tube is shown as a stepped arrangement with the counting point 131) at the stepped point.

Figures 6, 7, 8 and 9 show various configurations which the interior passage can assume, while Figures 10, 11 and 12 show various forms the outside configuration can assume.

In order to obtain the highest precision in counting the blood corpuscles, the diameter of the channeled tube should range between 4 to 50 microns, and it is further recognized that a channeled tube may be used only for one type of count, i. e., a special channeled tube may be used, for example, in doing platelet counts only and thus the inside diameter of the channeled tube would be limited in size from 4 to 8 microns, while the inside diameter of a channeled tube designed for red blood cell counts would be limited in size from 8 to 16 microns, etc. The channeled tube used would be selected by the test to be done.

In using the present invention, a portion of the specified dilution which has been agitated and thoroughly mixed is introduced into the stationary, vertical channeled tube from the pipette in which the dilution was made. A moment is allowed for the fiuid to come to rest. The blood cells will then rise by simple buoyancy and can be individually counted as they pass the counting point.

There are two possible Ways to decipher. the count. But before an explanation is made, several factors should be remembered. In the initial dilution, a specific volume of blood was measured and then diluted. A portion of the diluted specimen was then introduced into the channeled tube, but it was not necessary to measure the volume that was introduced as long as the volume was sutficient to fill the channeled tube'to a point above the counting point. Consequently there is not a measure of volume, but a measure of dilution. The temperature is held at room temperature and the pressure is constant enough to be infinitesimal. Viscosity of the diluted specimen is also constant due to the larger proportion of diluting fluid used. As counting begins there is only one factor actively involved, dilution.

The count may then be deciphered in two possible Ways. First, the counting may be done for a predetermined length of time. If this procedure is used, the end result is a counted number of. cells for a known length of time. For example, a count may be done by counting the cells that pass the counting point during a two minute period. With all factors, including dilution, held constant, the number of cells actually counted is the answer. If one specimen contains fewer cells than another specimen the former will tabulate alower figure. It is possible to standardize the answer with the present method used in counting blood cells and platelets, but it is neither necessary nor advised. 7

Second, the counting may be done for a predetermined number of microscopic bodies. If this procedure is used,

the end result is a measured length of time for a counted number of microscopic bodies. For example, a count is started and timed until 5900 bodies pass the counting point. The answer obtained is in. minutes and seconds. For example, one specimen might have. a 1'45" count while another specimen may have a l'53.9" count. However, the first method of deciphering the count is preferred for several reasons. First, it is usually easier for. one to think in simple units. Second, the break-down into minutes and seconds. might greatly. lengthen the time spent in counting. Third, the specimen with the greater number of bodies per unit volume would give a low figure if done in minutes and seconds, and the specimen with the fewer bodies per unit volume would give a big figure if done in minutes and seconds. This seemsrto be prohibitive for ease in calculation.

At this point it becomes plain as to the advantages of my method over the method commonly used. in the laboratory. Firstly, the accuracy is far more perfect because a volume is not counted, only a dilution. Both volume and dilution enter into the present method commonly used. Secondly, the accuracy is far more perfect because the number of cells counted by my method would be far in excess of the number counted in the present method commonly used. The greater number of cells that are counted allows less error to occur. Thirdly, the time consumed for each count is less by use of my method and thus saves valuable time for the technician. Fourthly, human error is reduced-only to the technique of pipetting.

As previously pointed out, any suitable counting means may be employed for counting the corpuscles as they pass the counting point but a preferred method is illustratively shown in Figure 1. As seen in Figure 1, numeral 11 indicates a light source casting its rays to lens 12. This lens condenses the .light source to the counting point 13 from which it passes to lens 14 and from there to photoelectric cell 15. Also provided is an energy source 16, an amplifier 17 and a tabulator 18. This counting apparatus is'shown in the previously mentioned patent to Kielland. and forms no part of the present invention. The essential distinction over Kielland lies in placing the tube 10 in a vertical position to enable the corpuscles to rise by simple buoyancy.

It Will be apparent from the foregoing description that the present apparatus and method is Well adapted to accomplish the objects of invention.

It should, of course, be understood that the description' and drawings herein are illustrative merely, and that variouslnodifications and'changes may be made in the structure disclosed without departing from the spirit of the invention.

Having. thus described the invention, what is claimed is:

l. The method of measuring the microscopic bodies inasample of blood comprising the steps of diluting the blood. in a'suspending liquid medium whose density is greater than the density of the microscopic bodies, introducing. the; dilution into a tube, arranging the tube in a vertical position. to enable the microscopic bodies to move in a vertical direction with the liquid in static condition, and counting. the number of microscopic bodies passing a point on. the tube.

2. The method of measuring the microscopic bodies in asampleofblood comprising: the steps of diluting the blood. in a suspending liquid medium whose density is.

greater: than. thedensity of the microscopic bodies, intro ducing the. dilutionv into a tube, arranging the tube in a verticalposition to enable the microscopic bodies to move in. a vertical direction with the liquid in static condition.

References Citedin the file of. this patent UNITED STATES PATENTS

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