This serological test detects IgG autoantibodies directed against tissue transglutaminase (tTG). It is primarily and very important in patients suspected of having celiac disease who also have selective IgA deficiency. In this case, IgA tests (such as tTG-IgA and EMA-IgA) will be false negatives, while tTG-IgG will be positive if the patient has the disease. It is a highly accurate test when used appropriately.