wie testet man eine glutenunverträglichkeit — can a DNA test help?

Testing for gluten intolerance is not straightforward and requires medical evaluation. The term covers three distinct conditions: celiac disease (autoimmune), wheat allergy, and non-celiac gluten sensitivity (NCGS). For celiac disease, the gold standard is a duodenal biopsy while on a gluten-containing diet, preceded by serology (tTG-IgA). A DNA test for HLA-DQ2/DQ8 haplotypes can rule out celiac disease with high certainty (negative predictive value >99%), but a positive result does not confirm disease, as 30–40% of the general population carry these markers yet only 1–3% develop celiac. For NCGS, no validated biomarker exists; diagnosis is by exclusion and controlled gluten challenge. IgG blood tests for food intolerances, often marketed by consumer labs, are not recommended by medical guidelines (e.g., DGE, AGA) due to high false-positive rates and risk of unnecessary dietary restrictions. A DNA test alone cannot diagnose or confirm gluten intolerance – it only provides a risk indicator for celiac disease. Evidence is mixed: HLA testing is clinically valid for exclusion, but for NCGS it has no proven utility. Consumers should not rely on direct-to-consumer DNA tests and should seek proper medical diagnostics.