Clinical Experiences with a Test for Bile Salts in Urine.

Abstract

In a previous preliminary report 1 a test for bile salts in urine was given. The method consisted in the nephelometric determination of the cloudiness produced in bile salt containing urine by acid precipitation. Further experience with this test brought to light certain defects in the original technique. At first the urine was decolorized by the addition of charcoal. This had the obvious advantage of giving a test fluid relatively free of pigment. However it was found after repeated trials that even if the charcoal was extracted with boiling alcohol it was impossible to prevent some loss of bile salts due to adsorption on the charcoal. A further loss (probably by hydrolysis) occurred in boiling the acid alcohol urine mixture for the precipitation of albumin as described in the original technique. It was noted, however, that urine containing albumin could be acidified directly without the production of a cloud, provided it is not heated. A cloud will be produced in urine at room temperature if bile salts are present. Precipitation of urochrome by salts of various metals was also attempted and found to be impracticable as some loss of bile salts occurred in all methods tried.

Since attempts at decolorization and removal of albumin all resulted in considerable loss of bile salts, we tried to determine the clinical value of a method which would not involve loss of bile salts, although open to certain other sources of error. The following simple procedure was used. The urine to he tested is filtered. To a 5.0 cc. portion is added 5.0 cc. of normal sulfuric acid. To a second 5.0 cc. is added 5.0 cc. of distilled water. Both tubes are then compared in the nephelometer against a standard prepared as follows: A urine is secured from a normal individual which does not show a nephelometric cloud when acidified.