FT4 Chemiluminescence Analyzer Automated Chemiluminescence
Methodology
Chemiluminescence Immunoassay
Product Show 
FT4
Free Thyroxine (FT4) Kit (Chemiluminescence Immunoassay) is intended for in vitro quantitative determination of free thyroxine (FT4) content in human serum, based on NRM411 system.
Thyroxine, also called 3,5,3',5'-tetraiodothyronine, is a hormone synthesized and secreted by thyroid, which together with triiodothyronine (T3), play an important role in the regulation of human growth and development including metabolic rate, cardiovascular function, bone metabolism, gonadal function and nervous system. In blood circulation, 99.95% of T4 reversibly binds to carrier proteins such as thyroxine-binding globulin (TBG), few albumins and prealbumins, and the rest T4 remains in a free state. FT4 has metabolic activity, and is also the precursor of T3.
Clinical Significance
In hypothyroidism and hyperthyroidism patients, FT4 and thyroxine (T4) concentrations normally paralleling change. The FT4 assay is usually combined with the detection of FT4 and TSH for clinical diagnosis of thyroid function disorder. FT4 assay is also suitable for the curative effect monitoring of thyroid suppression therapy. The determination of FT4 has the advantage of being independent of changes in the concentrations and binding properties of these binding proteins; additional determination of a binding parameter (T-uptake, TBG) is therefore unnecessary.
Test Principle
The assay is a competitive immunoassay for quantitative determination of FT4 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. Sample, calibrator or control is mixed with Magnetic Microbeads Reagent and Antibody 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 FT4 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 FT4 assay is traceable to a NIFDC standard reference material (lot No. 150551-201203).
