Lay opinion vs evidence: Gluten Test

The question about a gluten test (e.g., IgG blood test or genetic test for celiac disease) is often driven by lay hopes for a simple dietary answer. The scientific evidence is nuanced: For celiac disease (an autoimmune condition), specific antibodies (tTG-IgA) and duodenal biopsy are the gold standard – a genetic test for HLA-DQ2/DQ8 can only indicate risk, not diagnose the disease. For non-celiac gluten sensitivity (NCGS), no validated biomarker exists; IgG tests for gluten or wheat frequently yield false positives and are not recommended by professional societies (e.g., DZG, ESPGHAN). Many direct-to-consumer tests exploit this uncertainty and market themselves as 'food intolerance tests.' The evidence is best graded as 'marketing' or 'unclear.' Caveat: Without medical evaluation, self-diagnosed gluten avoidance can lead to nutrient deficiencies and unnecessary dietary restrictions. If celiac disease or NCGS is suspected, consult a gastroenterologist.