[Validity of the H2 breath test and limits of blood xylose in the evaluation of malabsorption in children].

Many authors have recently discussed the real value of the xylose test in the evaluation of intestinal malabsorption, especially its correlation with the morphological damage of the duodenal-jejunal mucosa. In our study we have performed in 48 pediatric patients one-hour blood xylose test and breath H2 test, method used for the diagnosis of sugar malabsorption, in order to value small bowel function and to know indirectly small intestinal mucosal structure. We have compared the values of the xylose test with those of the breath H2 test and both with hystological findings. The D-xylose absorption test was performed using the technique described by Roe and Rice. A serum concentration of more than 25 mg/dl was considered normal. For the breath H2 test the technique described by Douwes was used. A hydrogen concentration lower than 20 p.p.m. in expired air was considered normal. All of the patients in whose breath hydrogen was not detected after lactose oral load (2g/Kg body-weight, maximum 50 g), underwent a second test with lactulose (0,8 - 1 g/Kg body-weight), is not absorbed. We performed this test to rule out a false negative result (2% of the normal population). On histologic criteria, the patients were assigned to one of three study groups. Group I: normal duodenal-jejunal mucosal structure (11 patients). Group II: structural abnormalities not diagnostic of celiac diseases (7 patients). Group III: mucosal structural abnormalities typical of celiac disease (30 patients). In the first group the one-hour blood xylose test was normal in 9 patients (81.81%), whilst the breath H2 test was normal in 11 patients (100%).(ABSTRACT TRUNCATED AT 250 WORDS)