Effect of oral microflora on interpreting hydrogen breath test

The technique of exhaled breath hydrogen monitoring is non-invasive, simple, and inexpensive. It has major advantages over traditional methods for the investigation of suspected small bowel bacterial overgrowth, small bowel transit time, or carbohydrate intolerance. The quality of information provided by the technique may be adversely influenced by extra-intestinal factors, some of which seriously impair the validity of test interpretation. A transient rise in exhaled breath hydrogen has been reported to occur soon after carbohydrate ingestion. The mechanism of this early post-prandial breath hydrogen peak has been recently studied and thought to be due to fermentation of the ingested carbohydrate by anaerobic microflora which are harboured in the mouth and oropharynx. The authors have attempted to study this hypothesis.