Test Kit Type:Free T4 Test Kit (CLIA)
Analytical Sensitivity:2 pmol/L
Linearity2 pmol/L to 100 pmol/L

Intended Use

FT4 iClia is a chemiluminescent microparticle immunoassay for the quantitative measurement of free thyroxine (FT4) in human serum/plasma. Clinically, it is mainly used to evaluate thyroid function. The assay kit is intended for in vitro diagnostic use.

Salient Features

  • Based on Competitive chemiluminescent microparticle immunoassay
  • Acridinium Ester (AE) based kit for more accurate results
  • Test result within 30 minutes
  • Analytical Sensitivity: 2 pmol/L
  • Linearity: 2 pmol/L to 100 pmol/L
  • Long shelf life: 12 months at 2-8oC
  • Onboard stability of reagents: 30 days at 2-8oC
  • Convenient pack size: 50 Tests & 100 Tests
  • Prompt service back-up


FT4 iClia is a “competitive” immunoassay using microparticle acridinium ester-labeled chemiluminescent technology.

In the first step, anti-FT4 antibody labeled magnetic microparticle and human serum/plasma are mixed and incubated in an assay tube. Next, FT4 conjugated acridinium ester is added and combined, AE labels FT4 and FT4 in sample compete for the binding site of anti-FT4 antibody on the binding magnetic particle, and the Microparticle FT4 antibody/ free FT4 immune complex is kept with the help of a magnetic separator. Unbound acridinium ester and other substance are removed by washing and finally the bound enzyme is detected by addition of Pre-Trigger Solution and Trigger Solution. The relative light unit (RLU) intensity is inversely proportional to the amount of FT4. According to the FT4 RLU-concentration standard curve, the RLU tested can be interpreted to FT4 concentration in the sample expressed as pmol/L.

For quantitative testing of free thyroxine (FT4), the FT4 iCLIA assay utilizes a predefined lot-specific Master Curve which is uploaded into the instrument through the reagent Master Calibration Curve barcode. Based on the Master Curve and results obtained by running two Calibrators, an instrument specific Working Curve is created, which is used to calculate pmol/L from the RLU obtained for each sample.


Performance Characteristics

Limit of Blank (LoB) :  <1.5 pmol/L

Accuracy: The accuracy of FT4 iClia is tested with 60 clinical specimens and compared with Roche CLIA. The accuracy co-efficient is >0.990.


  1. The test results are repeatable in within run precision testing with CV <10%.
  2. The test results are reproducible in between run precision testing with CV <10%.

Ordering Information

Product Name Pack Size Catalog No.
FT4 iClia 50 Tests IR037050
FT4 iClia 100 Tests IR037100

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