The determination of serum or plasma levels of Triiodothyronine (T3) is recognized as an important measurement in the assessment of thyroid function. Its effects on target tissues are roughly four times more potent than those of T4. Of the thyroid hormone that is produced, just about 20% is T3, whereas 80% is produced as T4. T3 and T4 are regulated by a sensitive feedback system involving the hypothalamus and the pituitary gland. Approximately 99.7% of the T3 circulating in the blood is bound to plasma proteins: TBG (30- 80%), TTR/TBPA (9- 27%) and Albumin (11- 35%). Only 0.3% of the circulating T3 is free (unbound) and biologically active. T3 plays an important role in the maintenance of the euthyroid state. Total T3 measurements can be a valuable component in diagnosing certain disorders of thyroid function. STORAGE AND STABILITY 1. Store the detector buffer at 2～30℃. The buffer is stable up to 18 months. 2. Store Aehealth TT3 Rapid Quantitative Test cassette at 2～30℃, shelf life is up to 18 months. 3. Test cassette should be used within 1 hour after opening the pack. PERFORMANCE CHARACTERISTICS Detection Limit: 0.5 nmol/ L; Linear Range: 0.5~10.0 nmol/L; Linear correlation coefficient R ≥ 0.990; Precision: within batch C.V. is ≤ 15%; between batches C.V. is ≤ 20%; Accuracy: the relative deviation of the measurement results shall not exceed ± 15% when the accuracy calibrator prepared by TT3 national standard or standardized accuracy calibrator are tested. Cross- Reactivity: The following substances do not interfere with the T4 test results at the indicated concentrations: TT4 at 500ng/ mL,rT3 at 50ng/ mL.