Thyroid Function Tests (TFTs) are a group of blood tests used to evaluate the function of the thyroid gland. The thyroid produces hormones that regulate metabolism, energy levels, and many other vital body functions. These tests help diagnose thyroid disorders, such as hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid).

• Purpose: Measures the level of TSH in the blood, which regulates the production of thyroid hormones. This is usually the first test done to evaluate thyroid function.
• Why it's done: To detect underactive (hypothyroidism) or overactive (hyperthyroidism) thyroid.
• Normal range: 0.4 - 4.0 mIU/L (milli-international units per liter).
• High TSH: May indicate hypothyroidism (low thyroid function).
• Low TSH: May indicate hyperthyroidism (overactive thyroid).