What does a high tTG IgA result mean?

A high tTG IgA (tissue transglutaminase antibody) level is a key serological marker for celiac disease. It indicates an immune response against the enzyme tissue transglutaminase, typically seen in untreated celiac disease. Sensitivity and specificity are high (>90%), but a positive result alone does not confirm the diagnosis. False positives can occur in other autoimmune conditions, infections, or liver disease. In IgA deficiency, the test may be falsely negative; then IgG-based tests (tTG-IgG, DGP-IgG) are recommended. According to guidelines, celiac disease diagnosis requires a duodenal biopsy showing characteristic histological changes (Marsh classification) and improvement on a gluten-free diet. A high tTG IgA is a strong indicator but not diagnostic on its own. Genetic testing (HLA-DQ2/DQ8) can rule out celiac disease but cannot confirm it. If celiac disease is suspected, consult a gastroenterologist. Note: This is not medical advice, but general information.