This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Physiology
[{'content': 'D xylose absorption test is used to assess which of the following conditions: \nSelect and explain. \nA. Colon cancer, B. PUD, C. Celiac disease, D. Ulcerative colitis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 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.', 'role': 'assistant'}]