Gluten antibody tests are a group of serological immunoassays that measure the presence and quantity of specific antibodies produced by the immune system in response to the consumption of gluten, a protein found in wheat, barley, and rye. These tests (especially Anti-tTG IgA and Anti-EMA IgA) are the cornerstone of the initial diagnosis of celiac disease, an autoimmune disorder that causes inflammation and damage to the lining of the small intestine when gluten is consumed.