Simple screening tests for malabsorption include:

A. Microscopic examination.

B. D-xylose absorption.

D. Small bowel x-ray series.

DISCUSSION: The 72-hour stool collection is quite sensitive and detects even mild malabsorption. As it requires careful stool collection timed by carmen red markers and documented dietary fat intake, it is not useful for screening. Microscopic examination of the stool can detect muscle fibers if protein malabsorption is present and with Sudan II staining can estimate fat content. D-Xylose absorption from oral ingestion of 5 gm., detected by a blood sample after 1 hour, is a simple and quite accurate test to identify carbohydrate malabsorption. Small bowel x-ray series, using barium contrast, can give very useful information on mucosal abnormalities, enteric fistulas, mechanical obstructions, and very importantly, intestinal motility and transit time.