The Tissue Transglutaminase IgA Antibody test, commonly referred to as the tTG IgA test, is a blood test used to help diagnose celiac disease. This test measures the level of antibodies in the blood that are produced in response to tissue transglutaminase, an enzyme that is found in the lining of the small intestine. In people with celiac disease, the immune system mistakenly identifies tissue transglutaminase as a threat and produces antibodies against it, leading to damage and inflammation in the small intestine. The tTG IgA test is highly specific and sensitive, making it a valuable tool in the diagnosis and management of celiac disease. It is important to note, however, that the test results can be affected by certain medications, medical conditions, and dietary factors, and should be interpreted in the context of other clinical and laboratory findings.