The D-xylose absorption or tolerance test is used for evaluating patients with possible malabsorption, especially if celiac disease (gluten sensitive enteropathy) is suspected. D-xylose is a pentose sugar with a molecular weight of 150.15 grams. It is passively absorbed from the small intestine (particularly the jejunum), with 30-40% of the absorbed amount excreted in the urine. Failure to excrete a certain amount of D-xylose in the urine is seen in enterogenous malabsorption; pancreatic enzymes are not required for D-xylose absorption. Patients with renal disease may show reduced urine excretion, and should also have plasma samples drawn at specified times during the test.

To read more or access our algorithms and calculators, please log in or register.