Preparation and Procedure of D-Xylose Absorption Test

Submitted on March 27, 2012

Xylose is a type of sugar saccharide that is vital for the human body’s cellular communication. It is common practice for some manufacturers to often substitute xylitol or xylose for sucrose or corn sweeteners in chewing gum and toothpaste as it does not contribute in any way to tooth decay. The substance is absorbed from the jejunum area of the small intestine and is significantly slower when administered orally to a child, but in adults the rates of absorption may depend on a number of other factors. Almost one quarter of the substance is excreted via the urine within five hours of ingestion, but will increase if the individual increases the intake of vegetables and fruits.

When D-Xylose Absorption Test is Conducted

A D-Xylose absorption test is primarily performed to measure the rate of d xylose absorption by the human body. The test is also very helpful in identifying the causing factors of conditions that are linked to the lack of xylose absorption such as chronic diarrhea, weakness and weight loss. If the individual suffers from malabsorption syndrome, the intestines are also unlikely to be able to effectively absorb vitamins, nutrients and minerals from the intestinal tract into the bloodstream. A D-Xylose absorption test is also useful in identifying the reason behind a child’s failure to gain any significant amount of weight.


For a period of about 24 hours prior to the procedure, the patient will be advised to avoid consuming any foods high in pentose such as jams, jellies and pastries. Certain over the counter medications are also known to hinder the results of a d-xylose absorption test and should be informed to the doctor before hand. The patient will also most likely be instructed to avoid eating or drinking anything other than water for about 4 hours before the test.


The patient will be asked to drink a d xylose solution after providing blood and urine samples taken from the first urination of the day. After about 2 hours for adults and 1 hour for children, another blood sample will be drawn. A third blood sample may also be drawn after a period of about 5 hours since the administration of the d xylose solution and the readings compared. It is also essential that there be no amount of menstrual blood, stool, pubic hair or any other foreign matter in any of the blood samples.