Understanding SIBO testing procedures

Small intestinal bacterial overgrowth (SIBO) occurs when bacteria that normally inhabit the colon multiply in the small intestine, causing bloating, abdominal pain, diarrhea, and nutrient malabsorption. Accurate diagnosis relies on well-established SIBO testing procedures, the most common of which is breath testing.

Hydrogen and methane breath testing

Breath testing is the gold standard among non-invasive SIBO testing procedures. Patients consume a sugar solution—typically lactulose or glucose—and breathe into collection vials at regular intervals over two to three hours. The samples are analyzed for hydrogen and methane gases produced by intestinal bacteria. Elevated gas levels, or an early peak within 90 minutes, indicate bacterial overgrowth in the small intestine.

Preparing for a SIBO breath test

• Avoid antibiotics and probiotics for at least two weeks before testing
• Follow a restricted low-carbohydrate diet for 24 hours before the test
• Fast for 12 hours before the start of the test
• Pause certain medications, such as proton pump inhibitors, if your clinician advises

Proper preparation is critical, as recent meals, smoking, or exercise can skew results and lead to false positive or false negative results.

Complementary testing and follow-up

While breath tests remain central, some practitioners use blood tests, stool analysis, or a advanced gut microbiome test to assess the broader microbial landscape and rule out overlapping conditions such as dysbiosis or irritable bowel syndrome. For those who want to monitor recovery over time, a gut microbiome test subscription with long-term testing can show how the gut flora responds to treatment.

Interpreting results and next steps

Positive results typically lead to treatment with antibiotics, herbal antimicrobials, or dietary changes such as a low-FODMAP protocol. Clinics and functional medicine practices can expand their diagnostic services through a B2B gut microbiome platform and thus improve patient access to comprehensive testing.

Discussing SIBO testing procedures with a qualified healthcare provider ensures accurate diagnosis and an effective, personalized treatment plan.