What does a low tTG IgA result mean?

A low tTG IgA (tissue transglutaminase antibody, IgA class) result is typically interpreted as negative or normal in celiac disease screening. It indicates that, with high probability, there is no active celiac disease, provided the individual does not have IgA deficiency. Important caveat: In IgA deficiency (prevalence ~2–3% in celiac patients), tTG IgA can be falsely negative; in such cases, tTG IgG or DGP IgG should be measured. A low value alone does not rule out celiac disease with 100% certainty, especially in very early stages, if a gluten-free diet was started before testing, or in children under 2 years. Clinical evaluation by a gastroenterologist remains essential. The test is a well-established biomarker with high sensitivity (~95%) and specificity (~98%), but it is not a standalone diagnostic criterion – according to guidelines (ESPGHAN, ACG), positive or borderline results warrant duodenal biopsy. A low result is reassuring, but if clinical suspicion persists, further investigation (e.g., total IgA, HLA typing, or biopsy) may be needed. Note: This is not medical advice; consult a physician for personal health decisions.