The Eagle Biosciences Human Intact Fibroblast Growth Factor 21 (FGF-21) ELISA Assay Kit is designed, developed and produced for the quantitative measurement of human intact FGF-21 in serum and EDTA-plasma sample. The assay utilizes the two-site ``sandwich'' technique with two selected antibodies that bind to different epitopes of human intact FGF-21. One of the antibodies is specifically binds to the N-terminal human FGF-21 (1-7) and the other is specifically to the C-terminal human FGF-21 (175-181). Assay standards, controls and patient samples are added directly to wells of microplate that is coated with an anti-human FGF-21 (1-7) specific antibody. Simultaneously, a horseradish peroxidase conjugated anti-human FGF-21 (175-181) specific antibody is added to each well. After the first incubation period, the antibody on the wall of microtiter well captures human FGF-21 in the sample and unbound proteins in each microtiter well is washed away. A ``sandwich'' of ``anti-FGF-21 antibody --- human intact FGF-21 --- HRP conjugated tracer antibody'' is formed. The unbound tracer antibody is removed in the subsequent washing step. For the detection of this immunocomplex, the well is then incubated with a substrate solution in a timed reaction and then measured in a spectrophotometric microplate reader. The enzymatic activity of the immunocomplex bound to human intact FGF-21 on the wall of the microtiter well is directly proportional to the amount of intact FGF-21 in the sample. A standard curve is generated by plotting the absorbance versus the respective human intact FGF-21 concentration for each standard on point-to-point or 4 parameter curve fit. The concentration of human intact FGF-21 in test samples is determined directly from this standard curve. Sample Types: serum, plasma. Range: 32.5 - 2000 pg/ml. Sensitivity: 1.7 pg/ml. Time: 2.5 hours ? The Eagle Biosciences Human Intact Fibroblast Growth Factor 21 (FGF-21) ELISA Assay Kit (enzyme-linked immunoassay kit) is intended for the quantitative determination of human Intact Fibroblast Growth Factor 21 (FGF-21) levels in serum. The Eagle Biosciences Human Intact Fibroblast Growth Factor 21 (FGF-21) ELISA Assay Kit is for research use only and not to be used in diagnostic procedures.