Thyroxine (T4) is a vital hormone produced by the thyroid gland and serves as a cornerstone biomarker for evaluating thyroid function. It circulates in the bloodstream in two forms: total T4 (bound and unbound) and free T4 (FT4), the latter being the biologically active form. T4 is regulated by thyroid-stimulating hormone (TSH) and acts primarily as a prohormone, later converted into the more potent triiodothyronine (T3). T4 is essential for regulating metabolism, thermogenesis, growth, and neurological development, particularly during early life stages. Abnormal T4 levels are strongly associated with thyroid disorders such as hypothyroidism and hyperthyroidism.
Clinically, T4 measurement—especially when paired with TSH—is a standard tool in diagnosing and managing thyroid-related conditions. It is included in newborn screening protocols to detect congenital hypothyroidism, preventing serious neurodevelopmental delays through early intervention. Beyond clinical diagnostics, T4 is studied in research focused on metabolic regulation, cardiovascular health, neurodegeneration, and hormonal gene expression. It is also being investigated in environmental and cancer studies as a biomarker for endocrine disruption and thyroid malignancy progression.
The T4 ELISA is a competitive immunoassay used for precise quantification of T4 in serum samples. In this format, T4 in the sample competes with an enzyme-labeled T4 (HRP conjugate) for binding sites on anti-T4 antibodies coated on the microplate wells. After washing away unbound materials, a colorimetric reaction is initiated with TMB substrate, producing a signal inversely proportional to T4 concentration. The color change is measured at 450 nm, and concentrations are calculated using a standard curve. This method allows for sensitive, accurate assessment of T4, supporting both clinical decision-making and advanced thyroid function research.
This product is manufactured in USA by Eagle Biosciences.