Limitations of xylose tolerance test as a screening procedure in childhood coeliac disease.

The usefulness of the xylose tolerance test as a screening procedure for coeliac disease has been reassessed in 54 children with suspected coeliac disease. 5- and 24-hour urinary excretion rates of xylose were of no value in discriminating between patients with and without coeliac disease; similarly, the 3-hour blood xylose concentration was nondiscriminatory. Three (15-8%) patients with subtotal villous atrophy and 8 (61-5%) with partial villous atrophy due to coeliac disease had one-hour blood xylose values which fell within the normal range. The effect of withdrawal or reintroduction of dietary gluten on sequential one-hour blood xylose levels was variable and generally unhelpful in predicting those patients who developed gluten-induced mucosal changes. The results of the present study emphasize the serious limitations of the xylose tolerance test as a screening procedure in childhood coeliac disease. It is recommended that the use of the urinary xylose test should be abandoned in the paediatric population. A normal one-hour blood xylose value does not exclude a diagnosis of coeliac disease even in young children who have never received a gluten-free diet. A clinical suspicion of coeliac disease remains the most important single factor in deciding whether to preform a jejunal biopsy.