I T. Failure of the hydrogen breath test to detect primary sugar malabsorption

SUMMARY Five patients with sucrase-isomaltase deficiency, and one patient with primary glucose-galactose malabsorption had no increases in breath hydrogen excretion after oral sucrose or glucose. Anaerobic incubation with sugars of stool suspensions from 5 patients with primary sugar mal-absorption produced a trace of hydrogen (17,ul) in only one, while those from 13 of 14 controls produced a mean hydrogen volume of 640,ul under similar conditions. Altered bacterial metabolism is a probable explanation. Breath hydrogen excretion did increase appreciably in 2 of these patients after oral lactulose showing that hydrogen excretion may vary according to the substrate. Therefore, observation of breath hydrogen excretion after lactulose is not recommended as a means of predicting false-negative breath tests with other sugars. The hydrogen breath test is not a reliable means of diagnosing primary sugar malabsorption in children. The detection of increased amounts of hydrogen in expired air after sugar ingestion has been proposed as a sensitive, reliable, and non-invasive means of detecting sugar malabsorption.1 The theoretical basis for the test has bee