Evidence check: tTG IgA in the context of Allergie

The tTG IgA test (tissue transglutaminase IgA) is a well-established biomarker for celiac disease, not for allergies. It measures the immune response to gluten, which in celiac disease leads to damage of the small intestinal lining. In the context of allergies, this test is not indicated – allergies are primarily diagnosed via specific IgE (e.g., to foods or inhalants). Confusion between celiac disease and wheat allergy is possible, but they are pathophysiologically and diagnostically distinct. Evidence for tTG IgA in celiac disease is human-strong (high sensitivity and specificity), but it is not relevant for allergy. Caveat: A positive tTG IgA should always be confirmed by duodenal biopsy before starting a gluten-free diet. Without clinical correlation, the test may lead to unnecessary dietary restrictions. MyBody-X does not include this test in the AllergieCheck; it belongs to celiac screening.