The D-xylose test in coeliac disease.

The results of more than 500 D-xylose loading tests are described. In almost half of the cases proven or suspected to be coeliac disease, the blood xylose level was low. In 69 patients the result was compared to that of small bowel biopsy. Abnormal levels were found in 98% of total or subtotal villous atrophy. It is therefore suggested to apply the test for screening in severe cases. Since with increasing age the absorption of xylose improves, this is to be considered when evaluating the test. At the time of gluten readministration the D-xylose test suggests the presence of histological changes well before their clinical manifestation. Therefore the result of the D-xylose test serves as an indication for small bowel biopsy. An abnormal D-xylose test after introduction of the gluten-free diet points to its deficiency.