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T4
The thyroid hormone, thyroxine (T4) is produced by the thyroid gland. An important component in the synthesis is iodine. The major form of thyroid hormone in the blood is thyroxine (T4). Thyroxine is converted to the active T3 (three to four times more potent than T4) within cells by deiodinases (5'-iodinase).
Thyroxine-binding globulin (TGB) is the major carrier protein for circulating thyroid hormone. Only a very small fraction of the circulating hormone is free (unbound) - T4 0.03%.
The thyronines act on the body to increase the basal metabolic rate, affect protein synthesis and increase the body's sensitivity to catecholamines (such as adrenaline) by permissiveness. The thyroid hormones are essential to proper development and differentiation of all cells of the human body. These hormones also regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds. Numerous physiological and pathological stimuli influence thyroid hormone synthesis. Thyrotoxicosis or hyperthyroidism is the clinical syndrome caused by an excess of circulating free thyroxine, free triiodothyronine, or both. Both T3 and T4 are used to treat thyroid hormone deficiency (hypothyroidism).
T4 ELISA:
Competitive immunoenzymatic colorimetric method for quantitative determination of total T4 (Thyroxine) in serum or plasma.
Principle of the Assay:
Microtiter strip wells are precoated with anti-T4 antibodies (solid-phase). T4 in the sample competes with added horseradish peroxidase labelled T4 (enzyme-labelled antigen) for antibody binding. After incubation a bound/free separation is performed by solid-phase washing. The immune complex formed by enzyme-labelled antigen is visualized by adding Tetramethylbenzidine (TMB) substrate which gives a blue reaction product. The intensity of this product is inversely proportional to the amount of T4 in the sample. Sulphuric acid is added to stop the reaction. This produces a yellow endpoint colour. Absorption at 450 nm is read using an ELISA microwell plate reader.
Specific performance characteristics:
Intraassay | Interassay | Analytic Sensitivity | Accuracy | |
CV% | CV% | µg/ml | ±SE | |
T4 | 9.6 | 8.7 | 0.04 | 97.8% ± 5% |
Correlation with commercially available T4 assay performed on 59 samples is r = 0.952
Order information:
ELISA | Number of Determinations | Product Number |
T4 | 96 | DNOV054 |
