Solid phase radioimmunoassay for determination of conjugated cholic acid in serum

A modified radioimmunoassay for conjugated cholates is presented. In this modification the antibody is chemically bound to Sepharose which enables a fast and very easy separation of bound and free fractions, which results in a good reproducibility (the coefficient of variation between samples is 4%). The whole procedure is carried out at room temperature and with a short incubation time (45 min). Serum can by analysed directly (no extractions or modifications needed). The assay is a suitable tool for liver function testing. A rough indication of total bile acid concentration in serum or bile can also be obtained with this assay.