The TSH (Thyroid Stimulating Hormone) test measures the level of TSH in the blood. TSH is produced by the pituitary gland in the brain and acts as the primary regulator of thyroid function. It signals the thyroid gland to produce and release thyroid hormones (T3 and T4), which control metabolism, energy production, body temperature, heart rate, and growth.
This is the most sensitive and widely used test for evaluating thyroid function. A high TSH level usually indicates an underactive thyroid (hypothyroidism), while a low TSH level typically indicates an overactive thyroid (hyperthyroidism). It is used to screen for thyroid disorders, diagnose hypothyroidism and hyperthyroidism, monitor patients on thyroid hormone replacement therapy (levothyroxine) or antithyroid medications, and evaluate thyroid nodules and goiter.
