The Full form of TFT is Thyroid Function Test. TFT is a collective term for blood tests used to check the function of the thyroid. TFTs may be requested if a patient is thought to suffer from overactive thyroid (hyperthyroidism) or underactive thyroid (hypothyroidism), or to monitor the effectiveness of either hormone replacement or thyroid-suppression therapy. It is also requested routinely in conditions linked to thyroid disease, such as anxiety disorder and atrial fibrillation. A TFT panel typically includes thyroid hormones such as thyroxine (T4), thyroid-stimulating hormone (TSH, thyrotropin) and triiodothyronine (T3) depending on local laboratory policy. TSH, thyrotropin (Thyroid-stimulating hormone) is generally increased in hypothyroidism and decreased in hyperthyroidism, making it the most important test for early detection of both of these conditions. The result of this assay is suggestive of the presence and cause of thyroid disease, since a measurement of elevated TSH generally indicates hypothyroidism, while a measurement of low TSH generally indicates hyperthyroidism. However, when TSH is measured by itself, it can yield misleading results, so additional thyroid function tests must be compared with the result of this test for accurate diagnosis. TSH is produced in the pituitary gland. The production of TSH is controlled by thyrotropin-releasing hormone (TRH), which is produced in the hypothalamus.