The cost of the nine thyroid function tests is usually around $400, which can vary from region to region and from hospital to hospital. The nine thyroid tests generally refer to five hormone tests and four antibody tests. The five hormone tests include total triiodothyronine, total thyroxine, free triiodothyronine, free thyroxine and thyrotropin. The four antibody tests are thyroglobulin antibodies, thyroid peroxidase antibodies, thyroid microsomal antibodies, and thyrotropin receptor antibodies. The five hormones are commonly used for abnormalities in thyroid function, such as hyperthyroidism and hypothyroidism, and the four antibodies are significant in the diagnosis of autoimmune thyroid disorders, such as Graves’ disease and Hashimoto’s thyroiditis. It is recommended to consult the local hospital for the specific cost of the nine thyroid function tests.