An Anti-Deamidated Gliadin Peptide IgA (DGP IgA) test detects specific antibodies your body makes against gliadin (a gluten protein) to help diagnose celiac disease, an autoimmune condition where gluten damages the small intestine, by identifying an abnormal immune response to gluten. This blood test shows if your immune system is reacting to gluten, but it’s often used alongside other tests, like tissue transglutaminase IgA (tTG-IgA), for a comprehensive celiac diagnosis, especially if IgA deficiency is suspected