SIBO Breath Test (Hydrogen/Methane Breath Test)

Noninvasive test that measures hydrogen and often methane in breath after ingesting a sugar solution; used to assess bacterial fermentation in the small intestine

Helps diagnose small intestinal bacterial overgrowth, and may also help evaluate carbohydrate malabsorption and related gastrointestinal symptoms such as bloating, abdominal pain, and diarrhea

Exhaled breath samples after oral glucose or lactulose solutio

Fast for 12 hours before the test; avoid antibiotics and probiotics for about 1 month; stop laxatives, fiber supplements, antacids, and prokinetics about 1 week before; avoid smoking and strenuous exercise before/during the test

Baseline hydrogen usually less than 16 ppm; a rise of more than 20 ppm over baseline within 90 minutes suggests SIBO