Malabsorption testing

December 21, 2008

This is a belated follow-up to Marci’s request for

more information on the malabsorption testing I mentioned a while ago.

D-xylose absorption test: If tests are inconclusive, one possibility is to get a

D-xylose absorption test to see how well your intestines are absorbing

food. If you have CD or damage to the intestines for some other reason,

you would have below normal absorption. In this case, it would be

important to determine the cause of the poor absorption. If all other

causes are ruled out, then the celiac diagnosis should be reconsidered and the

gluten-free diet tried to see if absorption is improved. This test

would not be specific for celiac, but if you had normal absorption it would at

least tell you if you can rule out CD.

This test can be done by blood or

urine. It tests absorption of carbohydrates.

Here is a good description of the test:

You can also test for fecal fat. If you are not

absorbing, you will have too much fat in your stool (this is called steatorrhea;

pronounced stat-o-ree-ah).

This algorithm gives a good picture of what other maladies

can cause malabsorption and the path to diagnosis:

For more on this type of testing:

You can find lots more on this type of testing by searching

on the various terms I have mentioned here.

I don’t really know enough to know which test would be

the best test in your circumstances. This is one to discuss with your

doctor. Keep in mind that malabsorption can be caused by other problems

besides celiac, so this is only an indication that your body isn’t

absorbing nutrients properly; it does not indicate the reason for the

malabsorption. I usually only suggest malabsorption testing when other

tests give no clear diagnosis of CD. If malabsorption is the problem and

other diagnoses are ruled out, then CD should be reconsidered. Keep in

mind that even a small amount of malabsorption can be a symptom of CD.

Pam Newbury

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