SIMULTANEOUS MEASUREMENT OF D-XYLOSE AND BUTTER-FAT ABSORPTION USING MICROMETHODS.

Most intestinal absorption tests require collections of stool or urine. Measuring the five-hour urinary excretion of D-xylose presents difficulties in very young subjects; catheterization may be required for accurate collections, and xylose excretion may depend on the volume of urine excreted during the test.In this study, D-xylose absorption was measured by the blood tolerance curve, and the determination of D-xylose concentration in whole blood was adapted to a microtechnique. Butter-fat absorption was determined by the timed change in serum turbidity after an oral dose of 0.5 g. butter-fat/kg. (as 15% cream). It was possible to administer the D-xylose (1.1 g./kg.) and butter-fat together without significant interference by either substance with absorption of the other. Both determinations could then be performed on capillary blood samples obtained by finger-prick at timed intervals. Results in normal subjects and in malabsorptive states indicate that the method provides a valuable screening procedure and a useful measure of progress during therapy.