A serological test to detect IgA antibodies directed against gliadin, a major protein component of gluten found in wheat, barley, and rye. These antibodies were historically used as a primary or adjunctive test in the diagnosis of celiac disease. However, they are now considered less specific than newer antibodies (such as anti-tissue transglutaminase IgA - tTG-IgA), but are still used in some contexts, particularly in assessing non-celiac gluten sensitivity (NCGS).