D-xylose absorption: MedlinePlus Medical Encyclopedia

D-xylose absorption is a laboratory test to check how well the intestines absorb a simple sugar (D-xylose). The test helps detect if nutrients are being properly absorbed.How the Test is PerformedThe test requires a blood and urine sample. These tests include:Clean catch urine specimenVenipuncture (blood draw)There are several ways to perform this test. A typical procedure is described below, but make sure you follow the specific instructions you are given.You will be asked to drink 8 ounces (240 ml) of water that contains 5 teaspoons (25 grams) of a sugar called d-xylose. The amount of d-xylose that comes out in your urine over the next 5 hours will be measured. You may have a blood sample collected at 1 and 3 hours after drinking the liquid. In some cases, the sample may be collected every hour. The amount of urine you produce over a 5-hour period is also checked. Your health care provider will tell you how to collect all of the urine during a 5-hour period.How to Prepare for the Tes...