470 PHYSIOLOGICAL CHEMISTRY 



2. Methylene Blue Reaction (Russo). 1 To 5 c.c. of urine add 4 drops of a o.i per 

 cent solution of methylene blue. In cases of typhoid fever, measles, smallpox and 

 certain other disorders there will be a change in color from blue to green. In 

 normal urine the blue color persists. The test is sometimes used as a substitute 

 for the diazo reaction (see p. 469). 



PHENOLSULPHONEPHTHALEIN TEST FOR KIDNEY 

 EFFICIENCY 



This test for renal function was devised by Rowntree and Geraghty. 2 

 It depends upon the injection into the tissues of a dyestuff which 

 is eliminated rapidly by the normal kidneys, and can be easily estimated 

 quantitatively in the urine. 



This dyestuff, phenolsulphonephthalein, is non-irritative to the 

 body either when taken by mouth or when injected into the tissues, 3 

 so that it does no harm to an already weakened kidney. 



The patient upon whom the test is to be performed is given 300-400 

 c.c. of water 20-30 minutes previously, in order to assure a free flow 

 of urine. 



The procedure is as follows : One c.c. of a solution containing 6 mg. of phenol- 

 sulphonephthalein 4 per c.c. is injected intramuscularly in the lumbar region, the 

 time of injection being noted. The patient is then catheterized and the urine as 

 it forms thereafter allowed to drop into a beaker containing 2 drops of 25 per 

 cent NaOH. The appearance of a red color in the alkalinized urine indicates 

 beginning excretion of the drug, the normal time being within 5 to 10 minutes 

 after its injection. Urine is now collected in one-hour samples. In patients 

 with obstruction to the flow of urine from the bladder the retention catheter is 

 stoppered and the urine drawn off at the end of each hour. Other patients may 

 simply be allowed to urinate at the hourly periods. 



To each hour sample of urine is added 25 per cent NaOH, drop by drop, until 

 the maximum intensity of color appears. This color will remain constant for an 

 indefinite period of time. Each sample is then placed in a 1000 c.c. volumetric 

 flask and diluted to the mark with distilled water. 



Comparison is made in a Duboscq or other colorimeter (see p. 508) with 

 a standard consisting of 3 mg. of phenolsulphonephthalein in 1000 c.c. of solu- 

 tion. The cylinder containing the standard may conveniently be placed at the 10 

 mm. mark. Since the volume of each urine sample is the same as that of the 

 standard, the percentage elimination of phenolsulphonephthalein in each may be 

 easily calculated as follows : 



1 Russo: Riforma med., No. 19, 1905. 

 Peskow: Semaine med., 103, 1912. 

 da Pozzo: Gaz. Osp. Clin., 35, 865, 1914. 



'Rowntree and Geraghty: Jour. Pharm. and Exper. Therap., i, 579, 1910: also Arch. 

 Int. Med., March, 1912, p. 284. 



3 Abel and Rowntree: Jour. Pharm. and Exper. Therap., i, 231, 1910. 



4 This solution is prepared by adding 0.6 gram phenolsulphonephthalein and 0.84 c.c. 

 of 2/N NaOH to enough 0.75 per cent NaCl solution to make 100 c.c. This gives the mono- 

 sodium or acid salt which is slightly irritant locally when injected. It is necessary to add 

 2-3 drops more 2/N NaOH which changes the color to a bordeaux red. This prepara- 

 tion is non-irritant. 



