The ImmunoDiagnostics FGF-21 immunoassay is a solid phase ELISA designed to measure levels of FGF-21 in human serum, plasma, or cell culture research.

The ImmunoDiagnostics Human FGF-21 Kit (ELISA) is a reliable and reproducible tool for the quantitative detection of FGF-21 production.  The assay is intended for use with human serum, plasma, or for cell culture supernatant.

Numerous application fields exist, but particularly:

  • Hepatology: FGF-21 is indicated as a stress-responsive hepatokine that is activated during liver pathogenesis and injury such as in diabetes or non-alcoholic fatty liver disease.
  • Oncology: Circulating FGF-21 has been found to be elevated in a variety of tumor types, including breast, renal cell carcinoma, and hepatocarcinoma.


FGF21 fibroblast growth factor 21 ELISA assay test kit

FGF-21 Antibody Coated Microstrips: One microplate, 12 strips with 8 wells each, 96 dry wells in total.  The wells are coated with a rabbit polyclonal anti- human FGF-21 antibody.  The microplate is sealed in a foil bag.  Any unused strips should be returned to the bag and resealed for future use.

Detection Antibody Solution: Concentrate (100x conc). One vial containing 0.12 mL of a biotin conjugated polyclonal anti- human FGF-21.  Detection antibody should be diluted with only the 1X Assay Buffer needed.

Assay Buffer: Concentrate (5x conc).  One vial containing 20 mL of buffer for dilution of the detection antibody.  If precipitates are observed in the concentrated buffer, warm at 37oC until the precipitates disappear.  Dilute 20 mL of 5x Assay Buffer with 80 mL diH2O to make a 1x concentration prior to use.

Human FGF-21 Standard: 1920 pg of recombinant human FGF-21 in a buffered protein base, lyophilized.  Reconstitute with 1 mL 1x Assay Buffer to prepare 1920 pg/mL standard stock.  Prepare a serial dilution series with 1x Assay Buffer.  The reconstituted standard stock can be aliquoted and stored at -80oC for one month.  Avoid repeated freeze/thaw cycles.

Wash Buffer: Concentrate (10x conc).  One vial containing 50 mL of 10x wash buffer.  If precipitates are observed in the 10x solution, warm at 37oC until the precipitates disappear. Prepare 1x Wash Buffer my mixing 50 mL of 10x Wash Buffer with 450 mL diH2O.

STP-HRP Solution: Concentrate (200x conc).  One vial containing 0.06 mL of 200x STP-HRP solution.  Briefly spin the 100x vial and dilute the desired amount of 200x STP-HRP solution 1:200 with 1x Assay Buffer to prepare the 1x solution.  100 μL of 1x solution are required per well.  Immediately return unused concentrate to 2-8oC storage.

Substrate Solution: One bottle containing 12 mL of TMB (3,3’,5,5’-Tetramethylbenzidine) substrate.  Ready-to-use.  Do not expose to light.

Stop Solution: One vial containing 12 mL of ready-to-use stop solution.

The FGF-21 ELISA is a quantitative sandwich enzyme immunoassay. Standard, samples, and any desired controls are pipetted into the wells pre-coated with solid-phase capture antibody. After washing away any unbound substances, a biotin-labelled detection antibody, specific for human FGF-21, is added to the wells, and any unbound antibody is washed out. Streptavidin-HRP conjugate is then added and a TMB solution is added to develop color in proportion to the amount of human FGF-21 initially bound. The color development is stopped by addition of an acidifying solution and the optical density is determined. By plotting a standard curve versus measured absorbance, the amount of antigen in the sample can be calculated. The concentration of the antigen is expressed in pg/mL.

The kit contains calibrators and can be used in any laboratory equipped with a plate reader. The kit is optimized for the quantitative determination of human FGF-21 concentrations in serum plasma, and cell culture supernatant samples. The test can provide results within 3 hours.

Example only!  Do not use for calculations

FGF-21 Fibroblast Growth Factor 21 ELISA Assay Measurement Test Kit

FGF-21 Fibroblast Growth Factor 21 ELISA Assay Measurement Test Kit

4 Parameter Curve


FGF-21 Fibroblast Growth Factor 21 ELISA Assay Measurement Test Kit

Log-log Regression Curve

Fibroblast growth factor 21 (FGF-21) is a haptokine—a hormone secreted from the liver—encoded by the gene FGF-21.  FGF-21 regulates simple sugar intake and preferences for sweet food via signaling through FGF-21 receptors in the hypothalamus and elsewhere in the brain.  Rodent liver FGF-21 expression is regulated by PPARα and levels rise substantially with both fasting and consumption of ketogenic diets.

FGF-21 stimulated glucose uptake in adipocytes and is additive in this effect with insulin.  FGF-21 has been shown to protect animals from diet-induced obesity when overexpressed in transgenic mice and to lower both blood glucose levels and triglycerides with administered to diabetic rodents.

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