KE10042 is a solid phase sandwich Enzyme Linked-Immuno-Sorbent Assay (Sandwich ELISA). The Mouse/Rat FGF-21 ELISA kit is to be used to detect and quantify protein levels of endogenous mouse/rat FGF-21. The assay recognizes mouse/rat FGF-21. An antibody specific for mouse/rat FGF-21 has been pre-coated onto the microwells. The mouse/rat FGF-21 protein in samples is captured by the coated antibody after incubation. Following extensive washing, another antibody of biotinylated specific for mouse/rat FGF-21 is added to detect the captured mouse/rat FGF-21 protein. For signal development, Streptavidin-HRP is added, followed by Tetramethyl-benzidine (TMB) reagent. Solution containing sulfuric acid is used to stop color development and the color intensity which is proportional to the quantity of bound protein is measurable at 450 nm with the correction wavelength set at 630 nm.