Improved nonradioactive method for routine clinical analysis for long- and medium-chain stool lipids

Abstract

The authors describe a simple, practical method for routine clinical determination of long- and medium-chain stool lipids. Stool lipids were extracted into a hot mixture of benzene/ethanol/water (12/59/29, by vol), saponified in 30 min without formation of ethyl esters, and titrated in a clear, one-phase medium to a sharp color change. CVs for the titration were 2, 1, and 1% for 0.05, 0.25, and 0.5 mmol of fatty acids, respectively. Interference of stool short-chain acids other than fatty acids was not statistically significant. The precision of sampling of stool homogenate was improved by analysis of two aliquots, one from the top and one from the bottom of the suspension. This method of sampling is a practical alternative to the unpleasant homogenization with a blender or to the addition of large quantities of bile salts. The accuracy of the method may be increased, in special cases, by removing potential interferants.