Objective: To compare the value of the differential sugar absorption test (SAT) with the blood and urine D-xylose tests (DXTs and DXTu) in diagnosing coeliac disease (CD) the SAT and the standard DXTs and DXTu were performed in 14 coeliacs with abnormal small bowel histology and in 12 patients with aspecific gastrointestinal complaints.
Methods: In the SAT a solution of lactulose (L) and mannitol (M) was given to the fasting patient after which the L/M ratio was measured in 5 h urine by gas chromatography. In the DXTs and DXTu a solution of 25 g D-xylose was given to the fasting patient and blood was drawn at 0, 30 and 120 min and urine was collected for 5 h, respectively.
Results: To measure the power in diagnosing CD of the SAT, DXTs 30 min, DXTs 120 min and DXTu, the test results were plotted in ROC curves and the areas under the curves (AUCs) were calculated. The AUCs were 0.97, 0.77, 0.78 and 0.63, respectively.
Conclusion: In our opinion, the DXTs and DXTu are no longer useful in the investigation of mucosal function of the small bowel.