T4 Total ELISA

Intended Use
The DRG T4 Total ELISA is an enzyme immunoassay for the quantitative in vitro diagnostic measurement of total Thyroxin (T4) in serum or plasma (EDTA, lithium heparin or citrate plasma).

Summary and Explanation
The thyroid hormones thyroxine (T4) and triiodothyronine (T3), are synthesized and stored in the thyroid gland after stimulation by thyroid-stimulating hormone (TSH) from the anterior pituitary gland and thyrotropin-releasing hormone (TRH) from the hypothalamus. Proteolytic cleavage of follicular thyroglobulin releases T4 into the bloodstream. The major form of thyroid hormone in the blood is T4, which has a longer half-life than T3. In humans, the ratio of T4 to T3 released into the blood is approximately 14:1. T4 is converted to the active T3 (three to four times more potent than T4) within cells by deiodinases. More than 99% of T4 is reversibly bound to the plasma proteins thyroxine binding globulin (TBG; 70%) thyroxine binding pre-albumin (TBPA; 20%), and albumin (10%).

T3 and T3 exert powerful and essential regulatory influences on growth, differentiation, cellular metabolism, and general hormonal balance of the body.

T4 is the basal parameter to evaluate hormone secretion of the thyroid gland. Diseases affecting thyroid function may present a wide array of confusing symptoms. Measurement of total T4, TSH, free T3 and free T4 by immunoassay are reliable and convenient methods to determine the presence of thyroid disorders in patients. Increased levels of T4 have been found in hyperthyroidism due to Grave's disease and Plummer's disease and in acute and subacute thyroiditis. Low levels of T4 have been associated with congenital hypothyroidism, myxedema, chronic thryoiditis (Hashimoto's disease), and with some genetic abnormalities.

NOT INTENDED FOR NEWBORN SCREENING.

For concrete data please consult the Instruction for Use in the download box on the top right side.