Mixing of the intestinal content and variations of fermentation capacity do not affect the results of hydrogen breath test

OBJECTIVE: Although the hydrogen (H(2)) breath test has been in use for many years for diagnosis of sugar malabsorption, research is still underway to improve its diagnostic accuracy. In this study, we investigated whether possible confusing factors caused by the ingestion of the test solution itself (such as the delivery to the colon of other fermentable substrates pre-existing in the small bowel lumen, the release of preformed H(2) trapped in the feces, or differences in the fermenting capacity of the colonic bacteria) may interfere with the increase of breath H(2) concentration, an expression of malabsorption of the test substrate. METHODS: In 25 patients with untreated celiac disease and 23 sex- and age-matched healthy volunteers, breath H(2) excretion was measured after ingestion of a 250-ml solution containing sorbitol, a poorly absorbed alcohol sugar. On 2 other separate days, 12 randomly selected subjects in each group underwent breath H(2) excretion measurement after ingestion of 250 ml of a sugar free, nonabsorbable electrolyte solution and 250 ml of a solution containing lactulose, a nonabsorbable disaccharide. RESULTS: After sorbitol ingestion, celiac disease patients showed a significantly higher breath H(2) excretion than did healthy volunteers. Otherwise, breath H(2) responses to electrolyte solution and lactulose showed no difference between the two groups of subjects. CONCLUSIONS: In a group of patients with sugar malabsorption, increased breath H(2) excretion does reflect malabsorption. The washout or the mixing of the intestinal content or intergroup difference of fermenting activity of the colonic bacteria do not represent interfering factors and do not modify the accuracy of the H(2) breath test in day-to-day clinical practice.