The Tissue Transglutaminase Antibody – IgA (tTG IgA) test is a blood test primarily used to help diagnose celiac disease, an autoimmune condition triggered by gluten (a protein found in wheat, barley, and rye).

What the test measures:
This test detects IgA antibodies produced by the immune system against tissue transglutaminase, an enzyme found in the small intestine. In people with celiac disease, exposure to gluten causes the immune system to produce these antibodies, which can damage the intestinal lining.