Triiodothyronine (T3) is one of the two primary active thyroid hormones circulating in the bloodstream, the other being thyroxine (T4). While only about 20% of T3 is secreted directly by the thyroid gland, the majority—approximately 80%—is generated through peripheral conversion of T4 via deiodination. T3 circulates in the blood mostly bound to transport proteins, including thyroxine-binding globulin, thyroid-binding prealbumin, and albumin, with only a small fraction (~0.3%) existing in its unbound, biologically active form. T3 plays a central role in regulating metabolism by increasing oxygen consumption and heat production across nearly all tissues, and is essential for normal growth, neurological development, and sexual maturation.
In both research and clinical settings, T3 is a vital biomarker for evaluating thyroid function and diagnosing thyroid-related disorders, especially hyperthyroidism. Elevated T3 levels often precede increases in T4, making it an early and sensitive indicator of thyroid overactivity. It is also critical in identifying T3-thyrotoxicosis, a condition where T3 is elevated despite normal T4 levels. However, T3 levels can be influenced by factors such as medications, physical stress, and non-thyroidal illnesses, so results must be interpreted with clinical context to differentiate true thyroid dysfunction from secondary effects due to other conditions.
The Total T3 ELISA assay provides a competitive immunoassay method for accurately quantifying T3 concentrations in serum samples. In this format, T3 in the sample competes with an enzyme-labeled T3 (HRP conjugate) for binding sites on anti-T3 antibodies immobilized on a microplate. After unbound substances are removed, a TMB substrate is added, and the resulting color change—measured at 450 nm—is inversely proportional to the T3 concentration in the sample. This assay enables sensitive and specific measurement of total T3, aiding in the diagnosis and monitoring of thyroid health in both clinical and research applications.
This product is manufactured in USA by Eagle Biosciences.