Xylose Absorption Test - Normal, High, Low

Xylose (d-xylose) is a simple sugar (carbohydrate) that is usually easily absorbed by the body.

This test determines how well someone absorbs xylose. It measures the level of xylose in the blood and urine after a standard amount is ingested in order to evaluate the person’s ability to absorb carbohydrates in general.

  • High blood and urine levels. With the xylose absorption testing procedure, high blood and urine levels of xylose are normal. They indicate good xylose absorption by the intestines. This suggests that the tested person’s symptoms are likely due to another cause, such as pancreatic insufficiency or bileinsufficiency.
  • High blood levels but low urine levels. This may be seen in someone with kidney dysfunction. In this case, it is the blood levels that will be used to evaluate the individual for malabsorption.
  • Low levels of blood and urine. This indicate poor absorption of xylose.

A variety of conditions that affect digestion and absorption may cause decreased xylose levels. These may include:

  • bacterial overgrowth in the intestines
  • parasitic infections
  • a shortened bowel (such as from surgery)
  • celiac disease.

Depending upon a person’s clinical situation, an abnormal xylose absorption test may be followed by additional blood or stool tests to try to isolate the cause and/or by a small-bowel biopsy to look at intestinal cells.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.