Serum T3

Triiodothyronine is a hormone synthesized and secreted by thyroid follicular cells. In addition to the synthesis of triiodothyronine in the thyroid gland, it is mainly converted from thyroxine in peripheral tissues. Although the concentration of triiodothyronine is much lower than thyroxine, the bioactivity of triiodothyronine is 3 to 5 times higher than that of thyroxine. Triiodothyronine is a specific indicator for the diagnosis of hyperthyroidism, and it has important reference value for estimating the recurrence of hyperthyroidism.