SERUM BILE ACID LEVELS IN HYPERCHOLESTEROLAEMIC PATIENTS.

A shortened method of estimating serum bile acids is described, based on extraction and the measurement of fluorescence in sulphuric acid solution at 37 degrees 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.