fT4(Free Thyroxine) ELISA Kit

    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience
    • competitive-ELISA-Elabscience

      Catalog number:E-EL-0122


      • 96T
      • 24T
      - +
      Price: $495

      Reactivity: Universal

      Detection Range: 1.56~100 pg/mL

      Sensitivity: 0.94 pg/mL

      Lead Time: 7~10 daysWelcome to order from local distributors.

      Add to cart Compare Bulk request

      Intended use

      This ELISA kit applies to the in vitro quantitative determination of  fT4 concentrations in serum, plasma and other biological fluids.

      Test principle

      This ELISA kit uses the Competitive-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with fT4. During the reaction,  fT4 in the sample or standard competes with a fixed amount of fT4 on the solid phase supporter for sites on the Biotinylated Detection Ab specific to  fT4. Excess conjugate and unbound sample or standard are washed from the plate, and Avidin conjugated to Horseradish Peroxidase (HRP) are added to each microplate well and incubated. Then a TMB substrate solution is added to each well. The enzyme-substrate reaction is terminated by the addition of stop solution and the color change is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. The concentration of  fT4 in the samples is then determined by comparing the OD of the samples to the standard curve.

      Assay type Competitive
      Format 96T
      Assay time 2.0h
      Reactivity Universal
      Detection Method Colormetric
      Detection Range 1.56—100 pg/mL
      Sensitivity 0.94 pg/mL
      Sample Volume 50μL
      Sample Type Serum, plasma and other biological fluids


      This kit recognizes fT4 in samples. No significant cross-reactivity or interference between fT4 and analogues was observed.

      Typical data

      As the OD values of the standard curve may vary according to the conditions of the actual assay performance (e.g. operator, pipetting technique, washing technique or temperature effects), the operator should establish a standard curve for each test. Typical standard curve and data is provided below for reference only.

      Concentration(pg/mL) O.D Average
      100 0.39
      50 0.511
      25 0.712
      12.5 1
      6.25 1.409
      3.13 1.785
      1.56 2.066
      0 2.453


      Intra-assay Precision (Precision within an assay): 3 samples with low, mid range and high level fT4 were tested 20 times on one plate, respectively.
      Inter-assay Precision (Precision between assays): 3 samples with low, mid range and high level fT4 were tested on 3 different plates, 20 replicates in each plate.

        Intra-assay Precision Inter-assay Precision
      Sample 1 2 3 1 2 3
      n 20 20 20 20 20 20
      Mean (pg/mL) 5.10 11.00 44.20 5.20 11.00 45.00
      Standard deviation 0.30 0.50 2.30 0.30 0.50 2.00
      C V (%) 5.88 4.55 5.20 5.77 4.55 4.44


      The recovery of  fT4 spiked at three different levels in samples throughout the range of the assay was evaluated in various matrices.

      Sample Type Range (%) Average Recovery (%)
      Serum (n=5) 92-106 99
      EDTA plasma (n=5) 90-101 96
      Cell culture media (n=5) 96-107 102


      Samples were spiked with high concentrations of fT4 and diluted with Reference Standard & Sample Diluent to produce samples with values within the range of the assay.

          Serum (n=5) EDTA plasma (n=5) Cell culture media (n=5)
      1:2 Range (%) 87-101 99-112 91-104
      Average (%) 93 106 98
      1:4 Range (%) 85-96 92-108 92-105
      Average (%) 90 98 100
      1:8 Range (%) 88-104 85-98 94-109
      Average (%) 95 92 101
      1:16 Range (%) 89-106 87-99 96-111
      Average (%) 97 94 103

      Kit components & Storage

      An unopened kit can be stored at 2-8°C for 1 month. If the kit is not used within 1 month, store the items separately according to the following conditions once the kit is received.

      Item Specifications Storage
      Micro ELISA Plate(Dismountable) 8 wells ×12 strips -20°C, 6 months
      Reference Standard 2 vials
      Concentrated Biotinylated Detection Ab (100×) 1 vial, 120 μL
      Concentrated HRP Conjugate (100×) 1 vial, 120 μL -20°C(shading light), 6 months
      Reference Standard & Sample Diluent 1 vial, 20 mL 2-8°C, 6 months
      Biotinylated Detection Ab Diluent 1 vial, 14 mL
      HRP Conjugate Diluent 1 vial, 14 mL
      Concentrated Wash Buffer (25×) 1 vial, 30 mL
      Substrate Reagent 1 vial, 10 mL 2-8°C(shading light)
      Stop Solution 1 vial, 10 mL 2-8°C
      Plate Sealer 5 pieces
      Product Description 1 copy
      Certificate of Analysis 1 copy

      Note: All reagent bottle caps must be tightened to prevent evaporation and microbial pollution.
      The volume of reagents in partial shipments is a little more than the volume marked on the label, please use accurate measuring equipment instead of directly pouring into the vial(s).

      Other supplies required

      • Microplate reader with 450 nm wavelength filter
      • High-precision transfer pipette, EP tubes and disposable pipette tips
      • Incubator capable of maintaining 37°C
      • Deionized or distilled water
      • Absorbent paper
      • Loading slot for Wash Buffer

      Assay Procedure

      elisa assay procedure 1

      1. Add 50μL standard or sample to the wells, immediately add 50μL Biotinylated Detection Ab working solution to each well. Incubate for 45 min at 37°C

      elisa assay procedure 2

      2. Aspirate and wash the plate for 3 times

      elisa assay procedure 3

      3. Add 100μL HRP conjugate working solution. Incubate for 30 min at 37°C. Aspirate and wash the plate for 5 times

      elisa assay procedure 4

      4. Add 90μL Substrate Reagent. Incubate for 15 min at 37°C

      elisa assay procedure 5

      5. Add 50μL Stop Solution

      elisa assay procedure 6

      6. Read the plate at 450nm immediately. Calculation of the results


      1. Growth and male reproduction improvement of non-thermal dielectric barrier discharge plasma treatment on chickens.
        IF: 2.588
        Journal: Journal of Physics D Applied Physics(2018)
        Products: E-EL-0079 E-EL-0122 
        Sample type: Serum
        Reactivity: Chicken
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      • Q&A (1)

      K***nSubmitted [ Dec 19 2018 ]

      Asked: Dear Elabscience, My name is Kevin Chang and I’m a RD who is in charge of reagent design in Skyla corporation. Below is our company website. http://www.skyla.com/index.aspx?lang=US So far, we’re designing our new generation Vet analyzer which will be able to detect free thyroxine (fT4). So, I’m searching for suitable antibody of anti-free thyroxine (fT4) antibody for Canine now. I’m wondering if you have any suitable antibody ? BTW, if there’s any question, please feel free to contact with me. And I’m looking forward to your reply soon.



      Y**iSubmitted [ Dec 19 2018 ]

      Answered: Dear Kevin,this is Yumi,glad to get your inquiry.Very sorry for you,this antibody is unavailable in our company,if you have any question later,please feel free to contact me,my email ID is yumi@elabscience.com best regards,

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