[Abnormal flora in the small intestine. Diagnostic evaluation of the H2 breath test]

Jejunal aspiration in order to diagnose intestinal bacterial overgrowth is more unpleasant for patients than breath testing. The object of this study was to compare the results of the glucose H2 breath test and the lactulose H2 breath test with the results of intestinal culture. On separate days, cultures of intestinal fluid collected from the Treitz region, glucose H2 breath tests (80 g glucose) and lactulose H2 breath tests (15 g lactulose) were undertaken in 20 patients with diseases predisposing to small intestinal bacterial overgrowth and in 20 controls. Twelve patients had bacterial overgrowth. Abnormal glucose H2 breath tests were observed in 11 patients, ten of whom had bacterial overgrowth. Glucose H2 breath tests were normal in seven out of eight patients without bacterial overgrowth. Only four patients had an abnormal lactulose H2 breath test. It is concluded that the glucose H2 breath test is acceptable for diagnosing bacterial overgrowth, whereas the lactulose H2 breath test in not.