If you want to know if your thyroid function is normal, you can go to the hospital and get a thyroid function test to determine it. Thyroid function tests include seven tests: triiodothyronine, total thyroxine, free triiodine, thyronine, free thyroxine, thyroid stimulating hormone, antitriiodothyronine, thyroglobulin antibodies and thyroid microsomal antibodies. In general, thyroid function tests are usually done in triplicate, i.e., free thyroid hormone, total thyroid hormone, and thyroid stimulating hormone levels, because the results of these hormone levels can initially reflect whether the thyroid gland is functioning normally. However, sometimes the doctor will add several other tests to the test to analyze which thyroid disorder is involved based on the results of these tests. A thyroid function test requires only 3-5 ml of venous blood, which is very easy and convenient and does not affect the patient. You should not take blood clotting medications for two weeks before the test, as they can have a significant impact on the test results. By doing these thyroid tests, you can know exactly how your thyroid gland is functioning, and if there are any abnormalities, they need to be treated promptly.