The thyroid gland is a gland found inside your neck, under your larynx. Your thyroid is responsible for producing metabolism hormones that control every function in your body. Hypothyroidism occurs when your thyroid produces too little thyroid hormone, a condition that is often linked to iodine deficiency.
Thyroid function tests
Thyroid function tests help to determine if your thyroid is not working correctly. These simple blood tests indicate thyroid health.
- TSH: A TSH test is done to find out if your thyroid gland is working the way it should. It can tell you if it's overactive (hyperthyroidism) or underactive (hypothyroidism). The test can also detect a thyroid disorder before you have any symptoms. Thyroid-stimulating hormone (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 hormone synthesised and secreted by the pituitary gland.
- Free T3: This test measures the amount of T3 available to the tissues, or free T3. Many doctors believe that evaluating the levels of free T3 is the best indicator of thyroid function. Hypothyroidism is a condition where T3 blood levels are low. This causes cellular dysfunction and metabolic breakdown
- Free T4: Free thyroxine (free T4) tests are used to help evaluate thyroid function and diagnosethyroid diseases, including hyperthyroidism and hypothyroidism, usually after discovering that thethyroid stimulating hormone (TSH) level is abnormal
- Reverse T3; The Reverse T3 (RT3) test measures the inactive form of the hormone T3 or Triiodothyronine. Certain conditions may cause the body to convert T4 into Reverse T3 instead of active T3 as it normally does. Elevated levels of Reverse T3 are common in people with hypothyroidism.
- Thyroid Peroxidase Antibodies: A TPO test detects antibodies against TPO in the blood. The presence of TPO antibodies in your blood suggests that the cause of thyroid disease is an autoimmune disorder, such as Hashimoto's disease.
- Thyroglobulin Antibodies: Measurement of thyroglobulin antibodies is useful in the diagnosis and management of a variety of thyroid disorders including Hashimoto's thyroiditis, Graves' disease and certain types of goiter.