Measurement of serum primary bile acid ratio by gas liquid chromatography and radioimmunoassay.

The application of a sensitive gas liquid chromatography (GLC) assay has enabled patients in different diagnostic groups to be differentiated on the basis of the ratio of the primary bile acids, cholic: chenodeoxycholic acid. Because this method is unsuitable for a routine clinical laboratory, the primary bile acid ratio (PBR) is determined by radioimmunoassay techniques (RIA), and the results were compared with GLC analysis. RIA provided comparable results in control subjects and patients with large-duct obstruction, but significantly higher PBR values were found in cirrhotic subjects.