Thyroid T-Uptake Chemiluminescence Immunoassay Kit

Methodology                                                                                                         

Chemiluminescence Immunoassay

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T-uptake                                                                                                                 

T-uptake Kit (Chemiluminescence Immunoassay) is intended for in vitro quantitative determination of thyroxine-binding capacity (TBC or T-uptake) in human serum, based on NRM411 system.
The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are transported in serum bound to the thyroxine binding proteins: thyroxine binding globulin (TBG), thyroxine binding prealbumin (TBPA), and albumin. TBG, TBPA, and albumin bind approximately 75%, 15% and 10% of the total circulating T4, respectively, and bind 38%, 27% and 35% of T3, respectively. The changes of thyroid hormone binding protein (such as TBG) can affect the concentration of free T3 and T4, and then stimulate or inhibit the synthesis and secretion of thyroid hormones. T-uptake assay can help assess the level of total T4 in the blood when thyroid hormone binding protein levels fluctuate.

Clinical Significance                                                                                              

In certain conditions such as pregnancy, estrogen therapy, infectious and chronic tiacve hepatitis, biliary cirrhosis or congenital disorders, the number of T4 binding sites is altered and these variations can produce abnormal T4 values in an individual with no thyroid disease. Since the T4 values or the T-Uptake values alone can produce misleading information, a free thyroxine index (FTI) can be calculated to provide a clinically useful and accurate estimate of circulating free thyroxine.

Test Principle                                                                                                          

The assay is a chemiluminescent immunoassay for quantitative determination of T-uptake in human serum based on chemiluminescence immunoassay technology. The Magnetic Microbeads Reagent contains protecting reagents and magnetic microbeads that are coated with a biotin labeled anti-TBG antibody, free anti-TBG antibody. The Antibody Reagent contains the protecting reagent 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 T-uptake 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 T-uptake assay is traceable to the Elecsys T-Uptake assay.