what is tsh on blood test

A TSH (Thyroid Stimulating Hormone) blood test measures the level of TSH in your blood. TSH is produced by the pituitary gland in your brain and it regulates the production of thyroid hormones by signaling the thyroid gland. These thyroid hormones control many important body functions, including metabolism, heart rate, digestion, muscle control, bone health, and brain function. The test is commonly used to check how well the thyroid gland is working. It helps diagnose if the thyroid is overactive (hyperthyroidism) or underactive (hypothyroidism). Normal TSH levels typically range from about 0.4 to 4.0 milliunits per liter (mU/L). High TSH levels usually indicate an underactive thyroid, while low TSH levels suggest an overactive thyroid. The test can also detect thyroid disorders early, even before symptoms appear. The test involves drawing blood, requires no special preparation, and results help guide diagnosis and treatment of thyroid-related health conditions. In summary, the TSH blood test is a key tool to assess thyroid health and hormone balance in the body. It measures the hormone that stimulates the thyroid to produce hormones essential for regulating many bodily functions.