Zöliakie Test: which blood markers matter?

For a celiac disease test, the key blood markers are tissue transglutaminase antibodies (tTG-IgA), endomysial antibodies (EMA-IgA), and deamidated gliadin peptide antibodies (DGP-IgA/IgG). tTG-IgA is the first-line screening test due to its high sensitivity and specificity. Because IgA deficiency occurs in about 2–3% of the population, total IgA should be measured to avoid false-negative tTG results; in such cases, IgG-based tests (DGP-IgG or tTG-IgG) are recommended. Antibody levels correlate with the degree of intestinal damage but can also be elevated in other autoimmune conditions. A positive serology alone is not diagnostic; confirmation requires duodenal biopsy with histological grading (Marsh classification). In children with tTG-IgA levels >10 times the upper limit of normal, some guidelines (e.g., ESPGHAN) allow omitting biopsy. Crucially, gluten must be consumed regularly before testing, as a gluten-free diet can normalize antibodies. Consumer home tests typically measure only tTG-IgA and lack clinical interpretation; they may serve as a screening tool but cannot replace a physician’s evaluation. The evidence for these markers is strong (human-strong), supported by extensive clinical studies and international guidelines.