What is the role of T3 in thyroid function tests?

T3 (Triiodothyronine) is one of the main thyroid hormones, and it plays a critical role in regulating metabolism, heart rate, and body temperature. In a thyroid function test (TFT), measuring T3 levels helps assess hyperthyroidism or other thyroid-related disorders. Elevated T3 levels usually indicate an overactive thyroid, while low levels suggest hypothyroidism. T3 is typically measured alongside T4 and TSH to provide a complete picture of thyroid health. Since T3 is the more active form of thyroid hormone, imbalances can lead to noticeable symptoms that require medical attention.