CPT® Code 86364

The CPT® Code 86364 refers to the tissue transglutaminase test, which is a specific immunological assay used to detect antibodies against tissue transglutaminase (tTG) in various immunoglobulin classes, primarily IgA and IgG. This test is particularly significant in the evaluation of celiac disease, a chronic autoimmune disorder triggered by the ingestion of gluten, a protein found in wheat, barley, rye, and oats. In individuals with celiac disease, the immune system mistakenly identifies gluten and tissue transglutaminase as harmful substances, leading to the production of autoantibodies. This immune response results in damage to the intestinal villi, which are small finger-like projections in the lining of the small intestine that play a crucial role in nutrient absorption. The damage to these villi can lead to malabsorption of essential nutrients, resulting in various gastrointestinal and systemic symptoms. Common symptoms associated with celiac disease include recurring abdominal pain, bloating, chronic diarrhea or constipation, weight loss, and iron deficiency anemia. The tTG antibody test is particularly valuable because it is highly sensitive, especially the tTG-IgA variant, which is the preferred test for diagnosing celiac disease in most patients. It is important to note that accurate test results require the patient to be on a gluten-containing diet, as the absence of gluten can lead to a lack of antibody production, rendering the test ineffective.