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What is D xylose absorption test is used to assess which of the following conditions: and explain in detail?
Ans. C Celiac diseaseRef: Methods in Disease: Investigating the Gastrointestinal Tract by Victor R Preddy pg. 43* D-xylose absorption test is a medical test performed to diagnose conditions that present with malabsorption of the proximal small intestine due to defects in the integrity of the gastrointestinal mucosa.* D-xylose is a monosaccharide, or simple sugar, that does not require enzymes for digestion prior to absorption. Its absorption requires an intact mucosa only.* In this test, the patient ingests D-xylose (a nondigestible but absorbable carbohydrate) by mouth, and then the urinary D-xylose is measured.* Urine excretion below certain levels (depending on the amount of D-xylose ingested) implies poor absorption of D-xylose and, therefore, disease of the small intestine.* Alternatively, a blood level of xylose is measured 2 hours after the D-xylose is taken by mouth. Low levels in the blood imply poor absorption. Abnormal D-xylose tests are most frequently associated with disorders of the small intestine such as celiac sprue.* Malabsorbtion can also occur in pancreatic insufficiency, but D-xylose test should be normal.