Estimation of cholesterol in bile: assessment of an enzymatic method

Cholesterol in bile has been estimated using two variants of the cholesterol oxidase method and compared with gas-liquid chromatographic (GLC) assay. As published, the enzymatic method seriously underestimated biliary cholesterol. This was due to interference by other constituents of bile, particularly bilirubin and lecithin. However, by dilution of reagents and samples in water and isopropanol respectively a close correlation with the GLC method is achieved. It is concluded that the cholesterol oxidase method as published is unsuitable for the estimation of cholesterol in bile, but in modified form it is simple, accurate and economical.