Breath Testing for IBS: Consensus Guidelines Coming Positives, negatives, and pitfalls remain

Breath testing for digestive disorders from lactose intolerance to Helicobacter pylori infection has been around for some time, and the use is increasing. But lack of standardization in indications, preparation, methodology, and interpretation have led to heterogeneity in clinical practice and research. Evidence-based data on the testing's utility in irritable bowel syndrome (IBS) specifically have been few, and the application varies widely among gastroenterologists. There are plenty of data substantiating that food poisoning triggers the bacterial hypertrophy that leads to IBS, he explained. "Neurotoxicity from food poisoning leads to bacterial buildup and causes a neuropathy of the gut," but overgrowth can also result from other conditions leading to intestinal stasis, including bariatric surgery, blind loops, adhesions, and Crohn's disease strictures. One area of discordance is the choice of testing substrate -- glucose or lactulose. Glucose is absorbed so easily it never reaches the colon, Pimentel noted. "If the glucose test is positive, most agree there's bacterial overgrowth in the small intestine, so some more conservative clinicians use glucose because a positive glucose test is very definitive. On the other hand, you miss overgrowth in the second half of the small bowel." The methane gas testing component of the breath test becomes extremely useful, since the presence of intestinal methane in addition to hydrogen will dictate therapy, Pimentel emphasized. "We published a double-blind study showing that if you have methane, which is linked to IBS-constipation, you need to add neomycin to rifaximin to have efficacy. Methane slows the gut, so if an IBS patient is constipated, a breath test become very important." http://www.medpagetoday.com/reading-room/aga/lower-gi/62608?xid=nl_mpt_DHE_2017-01-20&eun=g721819d0r&pos=4