Oct 12, 2026 · 1h 7m
SIBO testing rarely settles the diagnosis
#542: Small Intestinal Bacterial Overgrowth (SIBO) with Dr. Purna Kashyap
Bloating and diarrhea have many causes, while imperfect tests can lead to prolonged treatment without addressing the motility or anatomical problem underneath.
- 1SIBO symptoms overlap with celiac disease, carbohydrate maldigestion, bile acid malabsorption, and medication effects.
- 2Breath tests and commercial microbiome profiles have important limitations and should be interpreted alongside pretest probability.
- 3Treatment works best when it reduces bacterial burden while addressing recurrent symptoms, altered anatomy, or impaired motility.
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Dr. Kashyap explains why testing should be reserved for patients with high pretest probability, since abnormal results may commit them to prolonged treatment.
The brief
SIBO often enters the differential through nonspecific bloating, gas, and loose stools. Dr. Purna Kashyap starts by separating those symptoms from the risk factors that make bacterial overgrowth more plausible.
The episode widens the diagnostic lens to celiac disease, carbohydrate maldigestion, bile acid malabsorption, and medication effects, including metformin and semaglutide.
Neither small-bowel aspirates nor glucose and lactulose breath tests provide a true gold standard. Home microbiome profiles add uncertainty rather than reliable clinical direction.
Treatment may involve short or rotating antibiotic courses, but chronic suppression with one drug is discouraged. Prokinetics help selected patients and can worsen diarrhea in others.
The clearest lesson is that an abnormal test creates a commitment to potentially prolonged treatment, making high pretest probability and attention to underlying causes essential.