How are tTG IgA and allergy related?

tTG IgA (tissue transglutaminase antibodies) is a specific biomarker for celiac disease, an autoimmune enteropathy, not an allergy. Allergies are IgE-mediated hypersensitivity reactions. Some studies explore a possible association between celiac disease and increased allergy prevalence (e.g., atopic dermatitis, asthma), but the evidence is inconsistent and mostly observational. There is no robust causal link between tTG IgA and allergies. Consumers should understand: a positive tTG IgA test indicates celiac disease, not a food allergy. Conflating these concepts in some direct-to-consumer tests is misleading. Clinically, it is crucial to distinguish between IgE-mediated allergy and autoimmune celiac disease. If celiac disease is suspected, gastroenterological evaluation with duodenal biopsy is required. An allergy test (e.g., specific IgE) cannot be replaced by tTG IgA.