Total Thyroxine (TT4) Kit (Chemiluminescence Immunoassay)
Methodology
Chemiluminescence Immunoassay
Product Show 
TT4
Total Thyroxine (TT4) Kit (Chemiluminescence Immunoassay) is intended for in vitro quantitative determination of total thyroxine (TT4) content in human serum, based on NRM411 system.
Thyroxine (3,5,3',5'-L-tetraiodothyronine, T4) is a hormone synthesized and secreted by the thyroid gland, and plays an important role in regulating metabolism. T4 is reserved in thyroid follicular cavity binding to thyroglobulin and secreted into blood circulation in response to the pituitary hormone TSH (thyroid stimulating hormone). In the circulation, over 99% T4 reversibly binds to carrier proteins such as thyroxine-binding globulin (TBG), few albumins and prealbumins.
Clinical Significance
TBG concentrations remain reasonably constant in healthy individuals. However, pregnancy, excess estrogens, androgens, and glucocorticoids are known to alter TBG levels and may cause false thyroid values for thyroid function tests. Malfunction of pituitary, hypothalamus and thyroid gland may result in excessive (hyper) or below normal (hypo) release of T4 or T3. Thus, the TT4 assay can be used to detect primary and secondary thyroid malfunction and monitor the curative effect of thyroid suppression therapy.
Test Principle
The assay is a competitive immunoassay for quantitative determination of TT4 concentration based on chemiluminescence immunoassay technology. The Magnetic Microbeads Reagent contains protecting reagents and magnetic microbeads that are coated with biotin labeled T4 antibody. The Antibody Reagent contains the protecting reagents and acridinium ester labeled BSA-T4 conjugate. Auxiliary Reagent contains dissociating agent and protecting reagents. Sample, calibrator or control is mixed with Magnetic Microbeads Reagent, Antibody Reagent and Auxiliary Reagent to form a sandwich complex. After incubation and automatic magnetic separation conducted by the instrument, trigger solutions are added to generate chemiluminescent reaction and the relative light units (RLUs) are measured by a photomultiplier. A proportional relationship presents between the concentration of TT4 in the sample and the RLUs detected by the NRM411 system.
Packages 100 Tests/Box, 200 Tests/Box.
Storage and Stability
Sealed: Stable until the expiry date when stored at 2-8ºC.
Opened: Stable for 4 weeks for reagents. Stable for 1 week after dissolved/opened for solid control material/liquid control material. To ensure the kit's best performance, it is recommended to place opened kits in the refrigerator if it's not going to be used on board during the next 12 hours.
Do not use it beyond the expiration date.
Calibration and Traceability
Calibration
Each batch of kits contains specific calibration information, stored in the Calibration Card.
Traceability
The TT4 assay is traceable to a NIFDC standard reference material (lot No. 150551-201203).
