<prompt> A 41 year old patient presented with chronic diarrhoea for 3 months. A d-xylose absorption test was ordered to look for:Carbohydrate malabsorption due to mucosa diseaseCarbohydrate malabsorption due to chronic pancreatitisFat malabsorption due to mucosal diseaseFat malabsorption due to chronic pancreatitis  <response>: Ans is A Carbohydrate malabsorption due to mucosal disease The urinary D-xylose test for carbohydrate absorption provides an assessment of proximal small intestine mucosal function. Urinary D-xylose test: Principle D-xylose is a pentose. that is completely absorbed almost exclusively in the proximal small intestine and excreted subsequently in the urine. The level of excreted D-xylose in urine is estimated. Any decrease in its level in urine means abnormality in carbohydrate absorption in proximal intestine. Procedure interpretation 25g D-xylose is given and urine is collected for 5 hrs. An excretion of 4.5e primarily reflects the presence of duodenal jejuna mucosal disease. 