Thyroid-stimulating hormone (also known as thyrotropin, thyrotrophic hormone, TSH, or hTSH for human TSH) is a pituitary hormone that stimulates the thyroid gland to produce thyroxine (T4), and then triiodothyronine (T3) which stimulates the metabolism of almost every tissue in the body. It is a glycoprotein hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland, which regulates the endocrine function of the thyroid.

Thyroid function tests include thyroid peroxidase autoantibodies (Anti-TPO), thyroglobulin autoantibodies (Anti-Tg), free and total triiodothyronine (T3), free and total thyroxine (T4), thyroid stimulating hormone (TSH) and T-Uptake. Thyroid stimulating hormone is the primary screen test for thyroid function with results that initiate the other tests exploring thyroid function. The use of TSH tests in screening has prompted some POC facilities to perform in-office testing supported by high volume and test functionality on many benchtop immune analyzers. The world market for POC TSH tests is estimated at $67 million in 2014 and with 4.4% annual growth will reach $83 million by 2019. [source; kalorama information]