What Is an Antithyroglobulin Antibody Test?

‌Your thyroid is a small butterfly-shaped organ in the front of your neck. It has a lot of important roles, including making hormones that control your metabolism and help your body grow and develop. The thyroid makes a protein called thyroglobulin that helps make thyroid hormones thyroxine (T4) and triiodothyronine (T3).

Your Thyroid and Immune System Antibodies

‌Your immune system is a group of glands, cells, and organs that work together to keep your body safe from invading threats. White blood cells and lymph nodes are part of this system, but so are your tonsils, spleen, bone marrow, gastrointestinal tract, and skin. Threats are most often foreign matter like bacteria, viruses, chemicals, parasites, and other unwanted organisms. 

The immune system makes antibodies, which are proteins that bind to the proteins in foreign invaders. Your immune system can sometimes think a part of your body is foreign, and that’s when damage may occur.‌

‌Autoimmune disorders can affect many parts of the body, including the thyroid. An autoimmune condition is when your immune system attacks the proteins in your own body cells, even though they are not harmful or foreign. 

When your immune system thinks your thryoglobulin proteins are foreign, it sends out antibodies to get rid of the threat. If you have a thyroid autoimmune disorder, or if your doctor thinks you have an issue with your thyroid, they will order a test known as an antithyroglobulin antibody test.