What can the Zöliakie Glutenunverträglichkeit-Test tell you — and what not?

The celiac genetic test (HLA-DQ2/DQ8) can tell you whether you carry the main genetic risk factors for celiac disease. A negative result virtually rules out celiac disease (high negative predictive value). However, a positive result does not mean you have celiac disease — about 30 % of the population carry these variants but only about 1 % develop the condition. The test cannot diagnose active celiac disease, nor can it detect non-celiac gluten sensitivity (NCGS). For a confirmed diagnosis, additional serology (tTG-IgA) and duodenal biopsy while on a gluten-containing diet are required. Evidence is moderate (human studies, but no RCTs for standalone genetic testing). The test is useful as a risk screening tool but not as a standalone decision-maker for a gluten-free diet. Caution: a positive result may lead to unnecessary dietary restrictions without clinical confirmation.