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Triiodothyronine, Total (T3) Human ELISA

  • Regulatory status:RUO
  • Type:Competitive ELISA, Immobilized antigen
  • Other names:T3
  • Species:Human
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Cat. No. Size Price

RCD025R 96 wells (1 kit)
PubMed Product Details
Technical Data


Competitive ELISA, Immobilized antigen



Sample Requirements

50 µl/well


At ambient temperature. Upon receipt, store the product at the temperature recommended below.


Store the complete kit at 2–8°C. Under these conditions, the kit is stable until the expiration date (see label on the box).

Calibration Curve

Calibration Range

0.2–10 ng/ml

Limit of Detection

0.16 ng/ml

Intra-assay (Within-Run)

CV = 9.4%

Inter-assay (Run-to-Run)

CV = 9.7%

Spiking Recovery


Dilution Linearity



Research topic



Triiodothyronine (T3) and thyroxine (T4) are the two active thyroid hormones found in the blood stream. About 80% of T3 is produced by the deiodination of T4 in the peripheral tissue and the other 20% is produced directly from the thyroid gland. T3 is transported through the peripheral blood stream bound to serum proteins, namely thyroxine binding globulin, thyroid binding prealbumin and albumin. About 0.3% of the total T3 is unbound and is therefore considered the free fraction.
T3 has an influence on oxygen consumption and heat production in virtually all tissues. The hormone also plays a critical role in growth, development and sexual maturation of growing organisms.
T3 is one parameter used in the clinical diagnosis and differentiation of thyroid disease, particularly hyperthyroidism. In most hyperthyroid patients, both serum T3 and serum T4 levels are elevated. Serum T3 levels are a sensitive indicator of the impending hyperthyroid state often preceeding elevated T4 and free thyroxine index values. Serum T3 levels are clinically significant in both the diagnosis of thyroid disease and in the detection of T3-thyrotoxicosis. However, it has been demonstrated that T3 levels may be affected by a number of medications, acute and chronic stress, and a variety of acute and chronic non-thyroidal illnesses. It is therefore necessary to differentiate those results that are due to thyroid dysfunction from those related to non-thyroidal diseases.

Summary References (14)

References to Triiodothyronine

  • Bergmann PJ, Van Tricht L. Free triiodothyronine in hypothyroidism and in nonthyroidal illness. Clin Chem. 1994 Mar;40 (3):496-7
  • Chopra IJ. RIA of iodothyronines. In: Abraham GE eds. Handbook of radioimmunoassay. New York: Marcel Dekker Inc,. 1997:679;
  • Cohen JH 3rd, Ingbar SH, Braverman LE. Thyrotoxicosis due to ingestion of excess thyroid hormone. Endocr Rev. 1989 May;10 (2):113-24
  • Demers LM. Thyroid function testing and automation. J.Clin. Ligand Assay. 1999;22:38;
  • Ekins R. Measurement of free hormones in blood. Endocr Rev. 1990 Feb;11 (1):5-46
  • Ingbar SH, Braverman LE, Dawber NA, Lee GY. A new method for measuring the free thyroid hormone in human serum and an analysis of the factors that influence its concentration. J Clin Invest. 1965 Oct;44 (10):1679-89
  • John R, Henley R, Shankland D. Concentrations of free thyroxin and free triiodothyronine in serum of patients with thyroxin- and triiodothyronine-binding autoantibodies. Clin Chem. 1990 Mar;36 (3):470-3
  • Kalra J, Hart IR. Value of free thyroxine (FT4), free triiodothyronine (FT3), and sensitive thyrotropin (TSH) assay in the assessment of optimal thyroxine therapy. Clin Biochem. 1987 Aug;20 (4):265-7
  • Mullinger RN, Gates J. Free triiodothyronine in nonthyroidal illness. Clin Chem. 1993 Jul;39 (7):1555
  • Nauman JA, Nauman A, Werner SC. Total and free triiodothyronine in human serum. J Clin Invest. 1967 Aug;46 (8):1346-55
  • Oddie TH, Fisher DA, Dussault JH, Thompson CS. Triiodothyronine turnover in euthyroid subjects. J Clin Endocrinol Metab. 1971 Oct;33 (4):653-60
  • Pedersen KO. Simultaneous determination of the free thyroxine and triiodothyronine fractions in serum. Scand J Clin Lab Invest. 1974 Nov;34 (3):241-6
  • Weeke J, Orskov H. Ultrasensitive radioimmunoassay for direct determination of free triiodothyronine concentration in serum. Scand J Clin Lab Invest. 1975 May;35 (3):237-44
  • Wilkins TA, Midgley JE, Stevens RA, Caughey I, Barron N. Assay performance and tracer properties for two analog-based assays of free triiodothyronine. Clin Chem. 1986 Mar;32 (3):465-9
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