Abstract

A shortened method of estimating serum bile acids is described, based on extraction and the measurement of fluorescence in sulphuric acid solution at 37°C. The cholate and dihydroxy bile acid fractions are determined separately by measurements made one hour and 24 hours after preparing the solution.

About 1% of the serum cholesterol escapes separation and appears in the sulphuric acid solution; in its fluorescent properties it behaves in a manner almost identical with dihydroxy bile acids. As a result, the normal serum bile acids are overestimated by about 2 mg./100 ml. This effect is unimportant in cases of jaundice. In non-jaundiced cases with hypercholesterolaemia, the apparently raised serum bile acid levels are accounted for by the interference from cholesterol and there is no evidence that a raised serum cholesterol level is usually associated with raised serum bile acids.