US2186902A - Urine acetone test - Google Patents

Description

Patented Jan. 9, 1940 v UNITED s rts- 2,186,902 URINE AcEToNE-TEsr William B. Fortune, Indianapolis, Ind., assignor to Eli Lilly and Company, Indianapolis, Ind., acorporation of Indiana No Drawing. Application April '7, 1939, Serial No. 266,539

's'oiaims. (01. 23-230) It is the object of my invention to provid 'j simple, rapid, and convenient test for acetone in urineyand one that can readily be made by a physician in a sick room without laboratory equipment, and without the need of other liquid than the urine itself and conveniently some water, which may be ordinary tap water.

The usual procedure for testing for acetone in .urine'is one that requires considerable skill and experience, as well as some technical knowledge;

and it also requires the use of at least one reagent that is available only in liquid form. While this:

can be done in hospitals and in clinical laboratories, even there it involves some technical difficulties,'and such a large chance of error due to the personal equation of the technician that l the error is often as high as 50%; and it is practically impossible for the general physician to use in the ordinary home sick room. In that usual procedure for making this acetone test,

a color is produced at the interface between two liquid layers, involving not only skill and a great chance of error in connection with determining the color and what it indicates, but also. very considerable skill in keeping the two liquid layers separate, since even relatively slight mixing of the two layers makes the test inaccurate.

My. invention permits an accurate acetone test to be made readily and rapidly, even by unskilled persons, with no other apparatus than a test tube, with no liquid acid or alkali, with little or no chance of material error from the observers personal equation, and with no necessity for keeping two liquid layers separate and 1 for reading a color at a mere interface, because with my test the color is produced through the whole mass of a liquid. A physician can make my test in the sick room within three minutes, and know at once from his own observation what a patients condition is with respect to acetone in the urine.

Such immediate knowledge is desirable for the physician in many pathological conditions, in order that he may from the beginning conduct his treatment accordingly. Acetone is likely to occur in many conditions, such as nephritis and malnutrition, especially post-operative malnutrition, but most particularly and most dangerously in diabetic coma, to mention but a few; and sometimes the condition may be such that the sav-- the urine as the treatment progresses, so that.

prompt knowledge at any particular point the treatment is oitremendous value.

My acetone test meets the requirements of the physician in this respect.

- Inaccordance with my invention, I proceed; generally as follows:

I take a fixed quantity of urine to be tested, say 4 cc., desirably in a test tube bearing a mark indicating that amount. For reasons which will;

appear, I then desirably dilute the urine to twice its volume, with ordinary tap water if no other is available, as by adding 4 cc. of water if the original amount of urine was 4 cc., conveniently by adding that water to a second mark on the test tube; although this dilution step is not one that is essential to my. invention. ThenI add to the urine,=which has preferably been diluted as stat-ed, a soluble nitroprusside, a soluble carbonate that will give an alkalinity at least as great as pH 10, an ammonium salt, and a material which will cause the observed color to be that due to reflected light. The soluble nitroprusside is most conveniently sodium nitroprus-, side, although other alkali-metal nitroprussides may be used. The soluble carbonate is most conveniently sodium carbonate, although other soluble alkali-metal carbonates may be used. The

ammonium salt is most conveniently ammonium,

sulfate, although other ammonium salts may be used, such for instance as ammonium nitrateor ammonium chloride or ammonium citrate; or

even ammonium carbonate if the ingredients are added directly, although that is not suitable if theingredients are to be kept for some time before use, because of the instability-of ammonium carbonate. The'material which will cause the observed color to be that due to reflected'light is some finely divided insoluble material, such for instance as finely ground talc or marble; desirably with some protective colloid also present,

Sodium nitroprusside Sodium carbonate monohydrate 200-220 mg. Ammonium sulfatel 200-220 mg. Talc 15- 25mg. Soap ,5- 10 mg.

These ingredients are all dry reagents; and.

gelatin capsule, which may be carried in the action unit is desirable for Conventional Mg. acetone per Color designation 100 cc. of urine 1 Light-greenishyellow Faint trace 15-25. 2 Flesh Trace 40-60. 3 Light violet l. 1+ -80. 4 Medium violet- 2+ -110. 5 Deep violet 3+ -150. 6 Dark purple-blue l 4+ Greater than 150.

In making the test, the physician 1 l. Takes 4 cc. of the patients urine, by fillin the test tube to the first mark.

2. Adds 4 cc. of tap water, by adding tap water to the test tube to the second mark.

3. Dumps into the test tube the contents of one capsule containing the ingredients above referred to.

4. Shakes vigorously; and then allows the tube to stand for about two to two and a half minutes.

5. Then promptly compares the color of the test-tube contents with the colors of the color chart, to determine directly by matching the colors the content of acetone in the urine.

The dilution of the urine before adding the reseveral reasons. First, such dilution prevents the precipitation, or causes the re-solution, of salts such as calcium or magnesium carbonates, which may be present in the urine. Second, the dilution spreads the color over a larger range, and facilitates comparison with the color chart; and the color chart I prefer is graduated on the basis of the diluted urine, although one can be made and used which is graduated on the basis of undiluted urine. Third, by diluting the urine, and using the quantities of reagents indicated, the color produced corresponds rather closely to the color produced in the interface test now commonly made, and indeed so closely that a technician experienced in that interface test can often read the color produced by my test with substantial accuracy even without making actual comparisons with the color chart.

I claim as my invention:

1. A process for testing for acetone in urine, which consists in diluting a fixed quantity of the urine, and adding to the diluted urine a soluble nitroprusside, a soluble carbonate which will produce an alkalinity at least as great as pH 10, an ammonium salt, and a material which will cause the color produced to be that observed by reflected light, to produce a color which by comparison with a color chart indicates the quantity of acetone in the urine.

2. A process for testing for acetone in urine, which consists in adding to a fixed quantity of urine a soluble nitroprusside, a soluble carbonate which will produce an alkalinity at least as great as pH 10, an ammonium salt, and a material which will cause the color produced to be that observed by reflected light, to produce a color which by comparison with a color chart indicates the quantity of acetone in the urine.

3. A process for testing for acetone in urine, which consists in diluting to a fixed volume a fixed smaller volume of urine, and adding to the diluted urine a definite quantity of a fixed-proportion mixture containing sodium nitroprusside, a sodium carbonate, ammonium sulfate, talc, and soap, to produce a color which by comparison with a color chart indicates the quantity of acetone in the urine.

4. A process for testing for acetone in urine, which consists in adding to a fixed quantity of urine a definite quantity of a fixed-proportion mixture containing sodium nitroprusside, sodium carbonate, ammonium sulfate, talc, and soap, to produce a color which by comparison with a color chart indicates the quantity of acetone in the urine.

5. A reaction unit, which reaction unit contains in solid form a soluble nitroprusside, a soluble carbonate which is capable of producing an alkalinity as great as pH 10, a stable ammonium salt, and a material which when the contents of the reaction unit are put into solution will cause the observed color produced to be that due to reflected light.

6. A reaction unit, which reaction unit contains in solid form sodium nitroprusside, sodium carbonate, ammonium sulfate, talc, and soap.

' WILLIAM B. FORTUNE.