SIBO breath test (lactulose/glucose hydrogen, ± methane, 3-gas)

Pick Ordered or Not ordered to see the note.

Indicated when

• —Symptomatic patients with suspected motility disorders, or with prior luminal abdominal surgery (e.g. gastric or colonic surgery, especially with loss of the ileocecal valve), where SIBO is a recognized cause of bloating, gas, diarrhea, or malabsorption [1, 3]
• —Persistent bloating, gas, diarrhea, or unexplained malabsorption in a patient with a recognized risk factor for SIBO (e.g. scleroderma, diabetes with autonomic neuropathy, small bowel diverticulosis, or prior bowel resection), after excluding other causes

Not indicated when

• —Routine testing in every patient with IBS symptoms, without a specific risk factor for SIBO or persistent symptoms after standard IBS management
• —Breath testing in asymptomatic patients taking a proton pump inhibitor, since PPI use alone is not an indication [3]

Why not

Breath testing for SIBO is useful but imperfect: a North American multi-society consensus panel found that 'standardization is lacking regarding indications for testing, test methodology and interpretation of results' across the field [2], and a summary of the ACG guideline notes that 'current testing methods are limited in sensitivity/specificity' compared with the invasive gold standard of small bowel aspirate and culture, which itself has no standardized collection technique [3]. A positive result outside a validated protocol, or from a lab using nonstandard gas thresholds, can lead to unnecessary antibiotic courses.

Better first step

Confirm the clinical picture first (persistent bloating, gas, diarrhea, or malabsorption, plus a recognized SIBO risk factor or an appropriate indication such as suspected motility disorder or prior luminal surgery) before ordering breath testing, and use a standardized glucose or lactulose protocol with defined hydrogen and methane thresholds [2, 1].

Typical ND rationale

An ND may order a lactulose or glucose breath test, often the branded 3-gas 'trio-smart' panel measuring hydrogen, methane, and hydrogen sulfide, in a patient with bloating, gas, or altered bowel habits, reasoning that small intestinal bacterial overgrowth is an under-recognized and testable cause of these symptoms, particularly in IBS [4].

Ontario coverage & CONO orderability

OHIP status

unverified

Hydrogen breath testing for SIBO is explicitly listed in docs/research/ontario-coverage.md as absent from the current community Schedule of Benefits, and a full-text search of the 2026 Schedule for 'breath', 'lactulose', 'mannitol', 'hydrogen test' and 'methane' found no listing, so billing status if a physician ordered it is unverified. ND-ordered testing is privately paid regardless (Reg. 552 s.22(1)); Ontario ND clinics offer the branded 3-gas 'trio-smart' breath test directly to patients [4].

CONO orderable

Yes — CONO list #192

CONO 192 'Hydrogen breath test', breath specimen. The CONO list does not separately enumerate a methane or hydrogen-sulfide breath test; the same breath samples analyzed for multiple gases (as in the branded 'trio-smart' 3-gas test) are grouped under this one item.

Linked conditions

• dysbiosis ↗
• ibs ↗

Counselling script

“SIBO is a real condition, and breath testing has a place when there's a risk factor like previous bowel surgery or a motility problem, or bloating that hasn't settled with standard treatment. The test isn't perfectly accurate and depends on the lab following a careful protocol, so any result gets read together with your symptoms rather than on its own.”

Revisit if

• —Symptoms persist or worsen despite treatment
• —New alarm features develop (weight loss, GI bleeding, anemia)

References

1. [1]American College of Gastroenterology (2020). ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth. linkACG guideline: evaluates diagnostic criteria and optimal testing methods for SIBO
2. [2]North American Consensus (multi-society expert panel) (2017). Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus. linkNorth American consensus: standardization is lacking in breath-test indications, methodology, and interpretation
3. [3]Emory University Division of Digestive Diseases (guideline summary infographic) (2020). ACG Clinical Guidelines: Small Intestinal Bacterial Overgrowth (summary of Pimentel et al. 2020). linkBreath testing is the preferred noninvasive test but has limited sensitivity/specificity; gold-standard aspirate/culture is invasive with no standardized technique; avoid breath testing in asymptomatic PPI users; recommended indications include IBS, suspected motility disorders, and prior luminal abdominal surgery
4. [4]NDcare Clinics (2026). Naturopathic Diagnostic Testing in Toronto. linkExample of an Ontario ND clinic offering the branded 3-gas 'trio-smart' SIBO breath test directly to patients
5. [5]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkCommunity lab tests are insured only when ordered under the Schedule by an authorized prescriber
6. [6]Government of Ontario (e-Laws) (2026). Health Insurance Act, R.R.O. 1990, Reg. 552: General, s. 22 (insured laboratory services). linkInsured lab testing requires ordering by an authorized provider who has clinically assessed the patient
7. [7]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkTests ordered by anyone other than an authorized provider, including NDs, are not insured services