Xylose Absorption, D-Xylose Absorption, Xylose, Malabsorption
Xylose AbsorptionAbsorption of D-xylose is a useful test in the differential diagnosis of malabsorption. D-xylose absorption is normal in patients with intraluminal maldigestion caused by hepatobiliary disease or pancreatic insufficiency. D-xylose absorption is decreased in most patients with mucosal malabsorption and in some patients with malabsorption due to bacterial overgrowth.D-xylose is a five carbon monosaccharide present in some plants that is absorbed unchanged by the duodenum and jejunum. Renal excretion accounts for about half of the total d-xylose elimination in patients with normal renal function. Renal D-xylose clearance is approximately 87% of the glomerular filtration, reflecting net renal tubular reabsorption. Nonrenal elimination is presumably hepatic. Nonrenal clearance does not appear to be compromised until creatinine clearance falls below 30 mL/min.Patients should be well hydrated and fast for 6 hours prior to the test. Between 08:00 and 09:00, one SST tube of blo...