Thyroid Disease Antibodies That Contribute to Thyroid Disease Common Thyroid Antibodies By Mary Shomon Mary Shomon Facebook LinkedIn Twitter Mary Shomon is a writer and hormonal health and thyroid advocate. She is the author of "The Thyroid Diet Revolution." Learn about our editorial process Updated on December 02, 2021 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Ana Maria Kausel, MD Medically reviewed by Ana Maria Kausel, MD Facebook Twitter Ana Maria Kausel, MD, is double board-certified in internal medicine and endocrinology/diabetes and metabolism. She works in private practice and is affiliated with Mount Sinai St. Luke's/Mount Sinai West. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents Antibodies and Thyroid Disease Antibody Test Results What Anti-Thyroid Antibodies Mean Frequently Asked Questions Thyroid disorders can have many causes. Autoimmune disorders of the thyroid are the most well-understood. If you have symptoms of a thyroid disorder, your healthcare provider may order antibody tests. These tests can help identify the cause of your disease. They may also help your healthcare provider decide on a treatment plan. This article discusses anti-thyroid antibodies, what they do, and why you may need an antibody test. It will also help you understand what your test results mean. Verywell / Laura Porter Autoimmune Antibodies and Thyroid Disease The thyroid is a gland located in the front of your neck. It produces important hormones that help control your metabolism and other body functions. Your thyroid gets its instructions from the pituitary gland, a small structure in your brain. The pituitary gland releases thyroid stimulating hormone (TSH), which tells the thyroid gland to make thyroid hormone. Antibodies are proteins your immune system makes to help protect you against infections. Sometimes antibodies can mistakenly attack your own tissues. Some thyroid conditions happen because antibodies attack the gland and interfere with its normal hormone-making process. These conditions are called autoimmune diseases of the thyroid. There are several types of thyroid antibodies. Each one attacks a different target in the thyroid hormone production process. The most common thyroid antibodies are: Anti-thyroperoxidase (TPO) antibodies Thyroid stimulating hormone (TSH) receptor antibodies (TSHR-Ab)Anti-thyroglobulin (anti-Tg) antibodies Anti-thyroperoxidase (TPO) antibodies The most common thyroid antibodies attack thyroid peroxidase (TPO). TPO is an enzyme in the thyroid gland that helps produce two important thyroid hormones: Thyroxine (T4)Triiodothyronine (T3) TPO uses iodine, an important nutrient, to produce these hormones. Autoimmune antibodies stop TPO from using iodine. This causes hypothyroidism, which is when your thyroid doesn't make enough hormones. Anti-TPO antibodies cause inflammation that can eventually destroy all or part of your thyroid gland. The inflammation can also cause it to form nodules or to become enlarged. Anti-TPO antibodies are associated with an autoimmune condition called Hashimoto's disease. People with Hashimoto's disease may have low thyroid hormone levels, but high TSH levels. This is because the pituitary gland produces more TSH to try to tell the thyroid to make more hormone. In pregnant people, TPO antibodies are also associated with preterm labor and other problems. Hashimoto's Thyroiditis Facts It may take time for TPO antibodies to cause a measurable change in your TSH levels. You can have positive TPO antibodies for months or years before you are diagnosed with hypothyroidism. Some people with positive TPO antibodies never become hypothyroid. Thyroid Stimulating Hormone (TSH) Receptor Antibodies (TSHR-Ab) TSH starts the hormone-making process by binding to structures on the thyroid gland called TSH receptors. TSH receptor antibodies (TSHR-Ab) can imitate the action of TSH. This causes hyperthyroidism, when the thyroid makes too much hormone. TSHR antibodies are also called thyroid-stimulating immunoglobulins (TSI). High levels are associated with an autoimmune condition called Graves' disease. Anti-thyroglobulin (Anti-Tg) Antibodies Thyroglobulin (Tg) is a protein that helps the thyroid gland function properly. Anti-Tg antibodies attack thyroglobulin. This can cause hypothyroidism. Anti-Tg antibodies are also associated with Hashimoto's disease. Recap Thyroid antibodies attack different parts of the hormone-making process. This may cause the thyroid to make too much or too little hormone. Thyroid Antibody Test Results Antibody levels can be tested with a blood sample. The antibody test measures the amount of antibody per milliliter or liter of blood in "international units." Normal values are: TPO antibody: Less than 9 IU/mLThyroid-stimulating immunoglobulin antibody (TSI): Less than 1.75 IU/LAnti-Tg antibody: Less than 4 IU/mL Note that different laboratories may have different normal range values. What Anti-Thyroid Antibodies Mean for You Thyroid treatment is not based on antibody levels. Treatment is based on symptoms and thyroid hormone levels. Antibody tests are useful in finding the cause of your thyroid disease. They can also help identify subclinical thyroid disease, which is thyroid disease with mild or no symptoms. Positive thyroid antibodies suggest you could have autoimmune thyroid disease. Still, they are only a piece of the picture. They can help healthcare providers decide if treatment is needed. Healthcare providers will also consider your symptoms, family history, and other blood test results. You can have elevated thyroid antibodies and not require treatment. For example, if you don't have symptoms and your thyroid hormone levels are normal, your healthcare provider may not treat you. If you have mild symptoms or your thyroid levels are borderline, you are more likely to receive treatment. The presence of antibodies may confirm subclinical hypothyroidism. Early therapy might prevent disease progression, but this has not been proven. Summary Some thyroid conditions are caused by autoimmune disorders. These are conditions where the body produces antibodies that interfere with the thyroid hormone-making process. Thyroid antibodies may cause the thyroid to make too much or not enough thyroid hormone. An antibody test can determine the cause of your condition. Thyroid treatment is based on your symptoms. If you do not have symptoms, you may not need treatment. A Word From Verywell Autoimmune diseases usually only affect one or a few organs. Still, if you have one autoimmune disease, you have a greater chance of having another one. Autoimmune thyroid disease can be associated with other conditions thought to have autoimmune causes. This includes diabetes and inflammatory bowel disease. Frequently Asked Questions What are anti-TPO antibodies? These are antibodies that attack the thyroid peroxidase (TPO) enzyme, which produces thyroid hormones. They are associated with Hashimoto's disease and are a sign that the immune system is mistakenly attacking the thyroid gland. These antibodies interfere with TPO function and can lead to hypothyroidism. Why do people take a thyroid antibody test? A thyroid antibody test can be taken to help diagnose and treat thyroid disorders. They look for signs of an autoimmune thyroid disease, which can lead either to hypothyroidism (low thyroid function) or hyperthyroidism (overactive thyroid). What is Graves' disease? Graves' disease is an autoimmune disorder that results in hyperthyroidism. In this disease, the antibodies attack the thyroid gland and stimulate it to make an excess amount of thyroid hormone. Was this page helpful? Thanks for your feedback! Losing weight with thyroid disease can be a struggle. Our thyroid-friendly meal plan can help. Sign up and get yours free! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 4 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Vanderpump MP. The epidemiology of thyroid disease. Br Med Bull. 2011;99:39-51. doi:10.1093/bmb/ldr030 Fröhlich E, Wahl R. Thyroid autoimmunity: role of anti-thyroid antibodies in thyroid and extra-thyroidal diseases. Front Immunol. 2017;8:521. doi:10.3389/fimmu.2017.00521 Meena M, Chopra S, Jain V, Aggarwal N. The effect of anti-thyroid peroxidase antibodies on pregnancy outcomes in euthyroid women. J Clin Diagn Res. 2016;10(9):QC04. doi:10.7860%2FJCDR%2F2016%2F19009.8403 National Institute of Diabetes and Digestive and Kidney Diseases (NIH). Graves' disease. Additional Reading Behroozi-Lak T, Akbary A, Vazifekhah S, Naghavi-Behzad M, Mirza-Aghazadeh-Attari M. Association of hypothyroidism and anti-thyroid antibodies with preterm delivery: a cross sectional study. J Family Reprod Health. 2017;11(4):191-196. Kotwal A, Stan M. Thyrotropin receptor antibodies-an overview. Ophthalmic Plast Reconstr Surg. 2018;34(4S Suppl 1):S20-S27. doi: 10.1097/IOP.0000000000001052. Krátký J, Ježková J, Kosák M, et al. Positive antithyroid antibodies and nonsuppressed TSH are associated with thyroid cancer: a retrospective cross-sectional study. Int J Endocrinol. 2018. doi: 10.1155/2018/9793850.