[Enzymatic determination of cholesterol in bile without interference of bilirubin]

The authors describe an enzymatic method for cholesterol determination in bile after elimination of bilirubin interference. During sample pretreatment, bilirubin is oxidized by hydrogen peroxide produced by adding glucose, glucose oxidase and peroxidase. Excess hydrogen peroxide is oxidatively coupled with 4-amino-antipyrine and a phenolic derivative (P-hydroxybenzoic acid). Cholesterol is then measured by use of a CHOD-PAP kinetic fixed-time method adapted to two different centrifugal analyzers (Multistat and Monarch IL). This method has a good within-run precision (CV = 1.6%) and good linearity (up to 23 mmol/l). Results have been compared to gas-liquid chromatographic (method selected by the Lipids-Lipoproteins Commission of the SFBC). The allometric regression line is: y = 1.016 x - 0.07 with r = 0.9975 (P < 0.001).