82 METHODS FOR THE ANALYSIS OF URINE 



6 mg. of phenolsulphonephthalein l 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 five to ten 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 tune. 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 Hellige colorimeter with 

 a standard consisting of 3 mg. of phenolsulphonephthalein in 1000 

 c.c. of solution. The cylinder containing the standard may con- 

 veniently be placed at the 10 mm. mark. Since the volume of 

 each urine sample is the same as that of the standard, the per- 

 centage elimination of phenolsulphonephthalein in each may be 

 easily calculated as follows: 



Reading of Urine : Reading of Standard :: 100 : x. 



The amount of the drug eliminated normally is 40 to 60 per 

 cent during the first hour and 20 to 25 per cent during the second 

 hour, or a total of 60 to 85 per cent for two hours. The amount 

 of the drug excreted has been found to be independent of the 

 quantity of urine obtained. In case of delayed excretion the col- 

 lection of hourly samples may be continued until practically all 

 of the drug has been recovered in the urine. 



If it is desired to test the function of each kidney separately, 

 ureteral catheterization must be resorted to, the experiment 

 otherwise being performed as above described. 



1 This solution is prepared by adding 0.6 gm. 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 to 3 drops more 2/N NaOH 

 which changes the color to a Bordeaux red. This preparation is non-irritant. 



