wie testet man glutenunverträglichkeit — what are common causes?

Common causes of gluten intolerance include celiac disease (an autoimmune disorder), wheat allergy (IgE-mediated), and non-celiac gluten sensitivity (NCGS). Celiac disease is diagnosed via specific antibody tests (tTG-IgA) and duodenal biopsy; wheat allergy via IgE testing. NCGS has no biomarker and is diagnosed by exclusion. Direct-to-consumer DNA tests (e.g., for HLA-DQ2/DQ8) can only indicate genetic risk, not confirm disease. A positive genetic result without symptoms or antibodies does not mean celiac disease. Crucially, a gluten-free diet must not be started before testing, as it can skew results. Evidence for celiac testing is strong, but for NCGS it is weak and often marketing-driven. Commercial stool or food sensitivity tests are unreliable. If gluten intolerance is suspected, consult a physician.