wie lange gluten essen vor zöliakie-test — can a DNA test help?

For a reliable celiac disease test (serology for tTG-IgA), adequate gluten consumption before blood draw is essential. Current guidelines (ESPGHAN) recommend a gluten challenge of at least 6 weeks, with a daily intake of about 3 g gluten (e.g., 1–2 slices of bread). If you are already on a gluten-free diet, you must reintroduce gluten; otherwise, antibodies will not be detectable. A DNA test (HLA-DQ2/DQ8) can reveal genetic predisposition. A negative result rules out celiac disease with high confidence (negative predictive value >99 %). However, a positive result does not confirm active disease – about 30 % of the population carry risk alleles, but only a minority develop celiac. The DNA test cannot replace the gluten challenge or a duodenal biopsy. It can serve as additional information, especially in cases of unclear serology or before starting a gluten-free diet. Important: Without prior gluten exposure, both serology and biopsy are worthless. Always consult a gastroenterologist if celiac disease is suspected.