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Clinician handoff

Sibo

Designed for a 60-second scan in primary care. Use this to explain why this theory fits, what would weaken it, and which tests are most worth discussing.

Why this still fits

I'm experiencing brain fog that worsens 30-90 minutes after meals, along with bloating and GI symptoms. I'd like to evaluate whether SIBO could be contributing. I've been tracking my symptoms relative to meal timing.

What would weaken it

  • -Is my fog pattern post-meal (SIBO) or more constant throughout the day (other causes)?
  • -Do I have bloating, gas, or altered bowel habits that suggest a GI origin?
  • -Should we check for underlying causes of SIBO: prior abdominal surgery, adhesions, diabetes, hypothyroidism, immunodeficiency, or chronic PPI use?
  • -If I've been on PPIs long-term, can we discuss whether I still need them or could step down?
  • -What's the retesting timeline after treatment? (ACG suggests 4-6 weeks)

Key points to communicate

  • Please document what findings would confirm this cause versus lower confidence.
  • I want an evidence-first workup with clear follow-up criteria.
  • Please note which competing causes should be checked in parallel if results are inconclusive.
  • Please separate metabolic, sleep, autonomic, and medication overlap before narrowing to one cause.

Tests and measurements to discuss

Need the fuller context? Use the test explainers for the measurement itself, or jump back to the tests section on the Sibo page to see how the tests fit the whole pattern.

SIBO breath test (lactulose or glucose) - I understand the North American Consensus recommends specific cutoffs

What this helps clarify: Screens for small intestinal bacterial overgrowth

Range context

Negative for H₂/CH₄ rise

How to use the result

Save the result with date and symptoms from the same week.

Trio-Smart test if hydrogen sulfide SIBO (ISO) is suspected

What this helps clarify: Advanced at-home breath test measuring hydrogen, methane, AND hydrogen sulfide to distinguish SIBO, IMO, and ISO subtypes.

Range context

H₂, CH₄, H₂S thresholds

How to use the result

Save the result with date and symptoms from the same week.

B12, ferritin, and fat-soluble vitamins to check for malabsorption

What this helps clarify: Iron storage marker that can affect energy, focus, and cognition.

Range context

40-100 ng/mL

How to use the result

Save the result with date and symptoms from the same week.

Consider whether underlying causes should be evaluated (see below)

SIBO Testing

Hydrogen-dominant: typical SIBO. Methane-dominant (IMO - Intestinal Methanogen Overgrowth): causes constipation, responds to different treatment. Hydrogen sulfide: newest subtype, associated with diarrhea and rotten egg odor.

What this helps clarify: Hydrogen-dominant: typical SIBO.

Peer-reviewed references

  1. https://journals.lww.com/ajg/fulltext/2020/02000/acg_clinical_guideline__small_intestinal_bacterial.9.aspx
  2. https://doi.org/10.1038/ajg.2017.46
  3. https://doi.org/10.1056/NEJMoa1004409