False positive urinary D-xylose test is seen in:

An abnormal test (<4.5 g excretion) indicates the presence of duodenal/jejunal mucosal disease. Like celiac disease, crohn's disease, Eosinophilic gastroenteritis and small intestinal lymphoma. The D-xylose test can also be abnormal in blind loop syndrome. False-positive study is seen in patients with ascites and pleural effusion. Ref: Harrison, E-18, P-2467.