What does a TFT (Thyroid Function Test) measure?

A Thyroid Function Test (TFT) is primarily used to evaluate the health of the thyroid gland. It measures the levels of various hormones that are crucial for thyroid function. The correct answer includes measuring Total T3 (tri-iodothyronine), Free T4 (thyroxine), and Thyroid Stimulating Hormone (TSH).

Total T3 helps assess the levels of the active thyroid hormone in the bloodstream, reflecting the gland's immediate hormone production. Free T4 is vital for understanding the unbound hormone that is biologically active in the body, providing insight into thyroid function. TSH is crucial as it stimulates the thyroid gland and is often used as an indicator of thyroid health; elevated levels might suggest hypothyroidism, while low levels could indicate hyperthyroidism.

Together, these measurements provide a comprehensive understanding of thyroid function, helping in diagnosing conditions like hyperthyroidism or hypothyroidism. Other choices either miss one or more core components of thyroid assessment, or they include hormones that are irrelevant to thyroid function.