D-Xylose Absorption Test
absorption test measures the level of D-xylose, a type of sugar, in a blood or
urine sample. This test is done to help diagnose problems that prevent the
small intestine from absorbing nutrients in
D-xylose is normally easily absorbed by the
intestines . When problems with absorption occur,
D-xylose is not absorbed by the intestines, and its level in blood and urine is
Why It Is Done
A test for D-xylose is done to:
- Check to see if
malabsorption syndrome is causing symptoms, such as
chronic diarrhea, weight loss, and weakness. A person with malabsorption
syndrome is unable to absorb nutrients, vitamins, and minerals from the
intestinal tract into the bloodstream.
- Find the cause of a child's
failure to gain weight, especially when the child seems to be eating enough
How To Prepare
For 24 hours before a D-xylose test, do
not eat foods high in pentose, a sugar similar to D-xylose. These foods include
fruits, jams, jellies, and pastries.
Medicines such as aspirin and
indomethacin can interfere with the results of a D-xylose test. For this
reason, your doctor may instruct you to temporarily stop these medicines before
Do not eat or drink anything except water for 8 to 12 hours before having this test. Children younger than 9 years old should not eat
or drink anything except water for 4 hours before the test.
A D-xylose test can take a long time. It might be a good idea to bring something you can do quietly while you wait, such as a book to read.
to your doctor about any concerns you have regarding the need for the test, its
risks, how it will be done, or what the results will mean. To help you
understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
The amount of D-xylose in urine and
blood samples is measured before and after you drink a D-xylose solution. To
begin the test, a sample of your first urine of the day and a sample of your
blood are collected.