Thyroid T3 and T4 tests are generally categorized as free T3, free T4, total T3, or total T4, with the cost of a single test ranging from$50-60. However, a thyroid function test is divided into three thyroid function tests, including T3, T4, and thyroid stimulating hormone. Because T3 and T4 alone have little clinical significance, together with the thyroid stimulating hormone test, we can distinguish between hyperthyroidism, hypothyroidism or normal function. To further improve the etiological examination, it is best to check the thyroglobulin antibody, and thyroid peroxidase antibody, which is a more complete thyroid function quintet. The cost of a single test for each of these ranges from$50-$60.