Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus.
Level 5 - mechanism / opinion, no new human data
Expert consensus statement and guideline development without new empirical human data.
PubMed 28323273 · doi:10.1038/ajg.2017.46
What was done
A panel of clinician-scientists convened to develop standardized guidelines for hydrogen and methane breath testing (BT) across five domains: indications, preparation, performance, interpretation of results, and knowledge gaps. Pre-meeting surveys were sent to 17 experts, 10 of whom attended a live meeting where 28 evidence-based statements were finalized and voted on anonymously.
What was found
Consensus was reached on 26 of 28 statements. Agreed standard testing doses were established as: 10 g for lactulose, 75 g for glucose, 25 g for fructose, and 25 g for lactose. For diagnosing small intestinal bacterial overgrowth (SIBO), a hydrogen increase of ≥20 p.p.m. by 90 min was deemed positive. Methane levels ≥10 p.p.m. were defined as methane-positive. For carbohydrate maldigestion, an increase in hydrogen of ≥20 p.p.m. from baseline was considered positive. The panel supported BT for carbohydrate maldigestion, methane-associated constipation, and bloating/gas evaluation, but not for assessing oro-cecal transit.
Why it matters
This consensus provides standard diagnostic cutoffs and preparation protocols to harmonize breath testing methodologies in clinical practice and research for SIBO and carbohydrate malabsorption.
Limits
Findings reflect expert consensus and literature synthesis rather than a primary clinical trial or new empirical testing dataset. The panel size was small (10 attending specialists), consensus failed on 2 of the 28 proposed statements, and diagnostic accuracy parameters (sensitivity, specificity) for the proposed cutoffs are not quantified in the abstract.
Cited by
- supports Breath tests for SIBO can determine whether the overgrowth is hydrogen-based or methane-based.