Presence of monohydroxy bile acids in the urinary precipitates: a pitfall in the analysis of urinary bile acids

The importance of the method of handling the urinary precipitates frequently present in urine samples, especially after freezing-thawing, for bile acid analysis is emphasized because of the presence of a considerable proportion of monohydroxy bile acids such as lithocholic and 3 beta-hydroxy-5-cholenoic acids. Filtration of the urinary precipitates may lead to the underestimation of these important bile acid species.