What are thyroid antibodies? Thyroid antibodies can be evaluated for by a blood test. Two such antibodies are anti thyroid peroxidase antibody (TPO Ab) and anti-thyroglobulin antibody (antiTg Ab). Most commonly TPOAb levels are evaluated in individuals with hypothyroidism.
What does it mean when TPOAb are positive? Upto 20% of the population may have positive TPOAb and have normal thyroid function. Having positive thyroid antibodies may increase the risk for developing thyroid dysfunction over time. However, you may have positive antibodies and not develop thyroid dysfunction or need medication. Positive thyroid antibodies are seen in autoimmune thyroid disease which include Hashimoto’s and Graves disease.
What is Hashimoto’s disease? It has other names such as chronic lymphocytic thyroiditis, or autoimmune thyroiditis. This is a condition where there is autoimmune destruction of the thyroid tissue leading to hypothyroidism or an underactive thyroid gland. Majority of individuals with Hashimoto’s disease will have positive TPOAb and anti-TgAb. In this condition, if enough thyroid gland destruction occurs, thyroid hormone replacement is needed to maintain normal thyroid levels in the blood.
What is Graves disease? Graves disease is an autoimmune condition that leads to an overproduction of thyroid hormones or hyperthyroidism. Individuals with this condition may have difficulty gaining weight, sleep disturbances, heat intolerance/sweating, increased appetite, increased bowel movements, increased heart rate and blood pressure along with eye disease. They can have positive TPOAb but also have antibodies that stimulate the TSH receptors on the thyroid cell or thyrocyte.