Thyroid stimulating hormone (TSH) is produced and secreted by the pituitary gland and stimulates the thyroid gland to produce T3 and T4. When TSH is elevated, low thyroid function may be indicated. However, if TSH is low it is indicative of high thyroid function. TSH is used as a first line screening tool to assess thyroid disease. Additionally, health care providers check TSH to monitor disease progression and treatment. Thyroid hormones regulate our body's metabolism and influence virtually every organ system in the body. They tell organs how fast or slow they should work. Thyroid hormones also regulate the body's consumption of oxygen and production of heat. Thyroid problems, such as an overactive or underactive thyroid, can severely affect metabolism. There are several thyroid conditions you may want to be aware of. Our program includes comprehensive testing of the thyroid gland (TSH) in addition to the thyroid hormones , thyroxine (T4) and triiodothyronine (T3). When the thyroid gland does not produce enough hormone, the body uses energy at a slower pace than it should. This condition, underactive thyroid, is called hypothyroidism. For a complete thyroid analysis it is best to also order FREE T3 and FREE T4 in addition to TSH. Also review our Complete Thyroid Panel for a very comprehensive test of the thyroid including TSH.