URINE 



551 



Interpretation. The amount of albumin occurring in the urine is 

 not necessarily an index of the severity or type of the disorder giving 

 rise to it. Hence no significant figures can be given. Normal human 

 urine probably contains a trace of albumin which is too slight to be 

 detected or determined by the usual procedures. The determination 

 of albumin may be of assistance in following the 

 course of kidney disturbances, but the results can be 

 interpreted only in the light of other clinical findings. 



2. Esbach's Method. This method depends upon the pre- 

 cipitation of protein by Esbach's reagent 1 and the apparatus 

 used in the estimation is Esbach's albuminometer (Fig. 169). 

 In making a determination fill the albuminometer to the point 

 U with urine, then introduce the reagent until the point R is 

 reached. Now stopper the tube, invert it slowly several times 

 in order to insure the thorough mixing of the fluids, and stand 

 the tube aside for 24 hours. Creatinine, resin, acids, etc., 

 are precipitated in this method, and for this and other reasons 

 it is not as accurate as the coagulation method. It is, however, 

 extensively used clinically. According to Sahli 2 the method 

 is "accurate approximately to one part per 1000," whereas 

 Pfeiffer 3 claims it is not accurate for less than one-half or for 

 more than five parts per 1000. 



Calculation. The graduations on the albuminometer indi- 

 cate grams of protein per liter of urine. Thus, if the protein 

 precipitate is level with the figure 3 of the graduated scale, this 

 denotes that the urine examined contains 3 grams of protein to 

 the liter. To express the amount of protein in per cent simply 

 move the decimal point one place to the left. In the case under 

 consideration the urine contains 0.3 per cent protein. 



Interpretation. See above. 



3. KwilecM's Modification of Esbach's Method. 4 Add 10 

 drops of a 10 per cent solution of FeCl 3 to the acid urine before 

 introducing the Esbach's reagent. Warm the tube and con- FIG. .169. 

 tents in a water-bath at 72 C. for 5-6 minutes and make the ESBACH'S ALBU^ 

 reading. MINOMETER. 



4. Turbidity Method of Folin and "Denis. 5 Principle. The albumin of the 

 urine is precipitated with sulphosalicylic acid and the turbidity produced com- 

 pared with that of a standard protein solution. 



Procedure. To about 75 c.c. of water in each of two 100 c.c. volumetric flasks 

 is added 5 c.c. of a 25 per cent solution of sulphosalicylic acid. To one flask is then 

 added 5 c.c. of the standard protein solution containing 10 mg. of albumin and to 



1 Esbach's reagent is prepared by dissolving 10 grams of picric acid and 20 grams of 

 citric acid in i liter of water. 



2 Sahli: Lehrbuch d. klin. Untersuchungs-Methoden, 5th Aufl., 1909. 



3 Pfeiffer: Berl. klin. Woch., 49, 114, 1912. 



4 Kwilecki: Munch, med. Woch., 56, p. 1330. 



5 Folin and Denis: Jour. Biol. them., 18, 273, 



1914. 



