[Comparison of commercially available radioimmunoassays for the determination of bile acids in serum (author's transl)].

Three commercially available radioimmunoassays for the determination of bile acids in serum were evaluated with respect to specificity and precision. The SLCG-radioimmunoassay (Abbott) measures chiefly cholic acid conjugates, and the CBA-radioimmunoassay (Becton-Dickinson) measures all conjugated bile acids, with an over-response to taurine metabolites. With respect to cross reactions, the performances of the CG-and the CBA-radioimmunoassays differed significantly from those stated by the manufacturers, the former showing a 32% response to taurocholic acid, the latter responding only 118% to taurochenodeoxycholic acid. At physiological concentrations of albumin + globulin, the recovery of defined cholanic acids was 85-101%. Good reproducibility was shown by the CG-radioimmunoassay in the range 0.5-10.0 mumol/l, by the CBA-radioimmunoassay in the range 1.0-25.0 mumol/l, and by the SLCG-radioimmunoassay in the range 0.5-3.0 mumol/l. There were no important differences in the inter-and intra-assay precision of the three methods.