The thyroglobulin antibody blood test measures the level of antibodies to thyroglobulin in the blood. Thyroglobulin is a protein produced by the thyroid gland that is involved in the production of thyroid hormones. Antibodies to thyroglobulin are immune system proteins that can attack and damage the thyroid gland, leading to thyroid dysfunction.

The thyroglobulin antibody blood test is used to help diagnose and monitor autoimmune thyroid diseases, such as Hashimoto’s thyroiditis and Graves’ disease. It may also be used to monitor patients who have had thyroid cancer, as thyroglobulin is often used as a tumor marker for certain types of thyroid cancer.

During the test, a healthcare provider will draw a small sample of blood from a vein in the arm and send it to a laboratory for analysis. The normal range for thyroglobulin antibody levels varies depending on the laboratory that performs the test, but generally ranges from less than 1 to 4 international units per milliliter (IU/mL).

Elevated levels of thyroglobulin antibodies may indicate an autoimmune thyroid disease or a history of thyroid cancer. However, some individuals may have elevated levels of thyroglobulin antibodies without having thyroid dysfunction. Therefore, a healthcare provider will interpret the results of the thyroglobulin antibody blood test in the context of the individual’s medical history and other test results.

Treatment for autoimmune thyroid diseases may include medications to manage symptoms and/or replacement therapy with thyroid hormone. Monitoring of thyroglobulin antibody levels may be used to help guide treatment decisions and monitor disease activity over time.