Serum TSH
About This Test
A Serum TSH (Thyroid-Stimulating Hormone) test measures the amount of TSH in the blood, produced by the pituitary gland to regulate thyroid function. It is the primary screening tool for thyroid disorders like hypothyroidism (high TSH, underactive) and hyperthyroidism (low TSH, overactive), typically with a normal range of 0.4 to 4.0 mIU/L.