An automated method for the determination of total bile acids in serum

Abstract

An automated modification of the earlier described enzymatic methods [10, 12] for the determination of total bile acids in serum is presented. The procedure involves two main steps, the inactivation of unspecific NADH generating enzyme activity in serum, followed by a transformation of the bile acids by a 3α-hydroxysteroid: NAD-oxidoreductase (3α-HSD) to the corresponding 3-keto compounds. Using an LKB reaction rate analyser, the NAD-containing 3 a-HSD preparation (Sterognost-3α) serves as starting reagent, and the NADH formed is measured as the increase in absorbance at 340 nm. The recovery of bile acid standards in 50 g/l albumin averaged 94% and in sera 91%. Accuracy was evaluated by comparison of the results on fourteen sera to gas liquid chromatography analysis; the means agreed within 2.2% (r = 0.99). A commercial control serum agreed within 1.5% to the recommended value. Precision was estimated on three pooled sera and found to be essentially the same for within run and day to day series, the stand...