Evidence check: tTG IgA in the context of gut health

The tTG-IgA test (tissue transglutaminase IgA) is a well-established serological marker for celiac disease. Evidence for its use in celiac diagnosis is strong (human-strong): sensitivity and specificity exceed 95% in active celiac disease. However, it is not a general 'gut health' marker. It detects a specific autoimmune response to gluten. In IgA deficiency (about 2–3% of the population), the test can be falsely negative; additional tTG-IgG or DGP-IgG should be measured. A positive test alone does not confirm celiac disease – duodenal biopsy remains the gold standard. In consumer tests (e.g., gut health home tests), tTG-IgA is often marketed as 'orientation', but interpretation requires medical follow-up. For general gut health issues (IBS, diarrhea, bloating without gluten link), the test provides no relevant information. Evidence for its use in non-celiac gluten sensitivity or other gut disorders is insufficient. Bottom line: tTG-IgA is a specific, well-validated test for celiac disease, not a universal gut health check. Consumers should understand that a positive result does not automatically mean gluten intolerance; further diagnostic workup is necessary.