Interval breath hydrogen test in glucose-galactose malabsorption.

A simple test is described for the diagnosis of monosaccharide malabsorption in infancy caused by a congenital defect of glucose and galactose transport. Increased hydrogen (H2) excretion in expired air after ingestion of sugar was used to diagnose this condition in an infant with severe diarrhoea after breast feeding. Abnormal amounts of H2 were excreted after oral administration of glucose and galactose, but not after fructose. A carbohydrate free diet supplemented with fructose resulted in rapid weight gain and disappearance of diarrhoea. The diagnosis of glucose-galactose malabsorption was confirmed by 14C-glucose transport studies on a jejunal mucosal biopsy specimen. These findings indicate that interval breath H2 estimation in mixed expired air is a non-invasive, reliable procedure for detection of monosaccharide malabsorption in infancy.