xyloseNOUN: A white crystalline sugar, C5H10O5, used in dyeing and tanning and in diabetic diets. Also called wood sugar.
http://www.bartleby.com/61/10/X0011000.html Xylose tolerance test Definition��� This test measures the intestines' ability to absorb D-xylose, a simple sugar, as an indicator of whether nutrients are being properly absorbed. How the test is performed��� An initial blood and urine sample are taken.Child or
adult:Urine collection:Collect a "clean-catch" ("midstream") urine sample. To obtain a clean-catch sample, men or boys should wipe clean the head of the ***** . Women or girls need to wash the area between the lips of the vagina with soapy water and rinse well. As you start to urinate, allow a small amount to fall into the toilet bowl (this clears the urethra of contaminants). Then, in a clean container, catch about 1 to 2 ounces of urine and remove the container from the urine stream. Give the container to the health care provider or assistant.Blood
collection:Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood). A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.You are given 25 grams of D-xylose in 8 oz. of water. Blood is collected after 2 hours, and sometimes again after 5 hours. Urine is re-tested after 8 hours. Urine excretion over a 5 hour period is also determined (all of the urine is collected for 5 hours). How to prepare for the test��� Fast for 8 to 12 hours before the test. Consult the health care provider about the need to withhold drugs that can affect test results (see "special considerations").How the test will feel���When the needle is inserted to collect the blood, a stinging sensation or prick will be felt. After the blood has been drawn, the puncture site may throb for a few minutes, and may feel bruised for a day or two.Urine is collected as part of normal urination with no discomfort.Why the test is performed���This test may be performed to help evaluate cases
of:* persistent diarrhea * unexplained weight loss * suspected malnutrition* general weakness This test is especially useful to distinguish absorptive problems of the intestines due to intestinal disease versus malabsorption due to disease of the pancreas.Normal Values��� The value varies depending on the amount of D-xylose administered. Usually the test is registered as either positive or negative. Positive indicates that D-xylose is found in the blood and/or urine and is therefore being absorbed by the intestines.blood: 25 to 40 mg/dl 2 hours after ingestionurine: 80 to 95% excreted within 5 hours of ingestionNote: mg/dl = milligrams per deciliter What abnormal results mean��� Lower than normal values may be seen
in:* Crohn's disease * Giardia lamblia infestation* hookworm infestation* lymphatic obstruction * radiation enteropathy * small intestinal bacterial overgrowth* celiac disease (sprue) * viral gastroenteritis * Whipple's disease What the risks are��� * excessive bleeding * fainting or feeling lightheaded* hematoma (blood accumulating under the skin)* infection (a slight risk any time the skin is broken)* multiple punctures to locate veinsSpecial considerations���Multiple tests may be necessary to determine the reason for malabsorption (inadequate absorption of nutrients from the intestinal tract).A failure to restrict activity may change test results.Drugs that can affect test results include aspirin, atropine, indomethacin, isocarboxazid, and phenelzine.Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
http://www.nlm.nih.gov/medlineplus/ency/article/003606.htm