Description:
FreeT4 is part of the regulating circuit of the thyroid gland and has an effect on general metabolism. Free T4 is measured together with Free T3 and TSH when thyroid function disorders are suspected. Since free T4 is the active form of thyroxine, it is thought by many to be a more accurate reflection of thyroid hormone function. This helps the doctor to determine whether the thyroid hormone feedback system is functioning as it should, and the results of the tests help to distinguish between different causes of hyper- and hypothyroidism. Thyroid hormone tests may be ordered to help evaluate a patient with an enlarged thyroid gland (a goiter) and to aid in the diagnosis of female infertility. If the doctor suspects that the patient may have an autoimmune-related thyroid condition, thyroid antibodies may also be ordered. Elevated Free T4 results may indicate an overactive thyroid gland (hyperthyroidism), and low Free T4 results may indicate an underactive thyroid gland (hypothyroidism). The test results alone are not diagnostic but will prompt the doctor to perform additional testing to investigate the cause of the excess or deficiency. Both decreased and increased thyroid hormone results are associated with a variety of temporary and chronic thyroid conditions.