KE00250 is a solid phase sandwich Enzyme Linked-Immuno-Sorbent Assay (Sandwich ELISA). The Human Follistatin ELISA kit is to be used to detect and quantify protein levels of endogenous human Follistatin. The assay recognizes human Follistatin. An antibody specific for human Follistatin has been pre-coated onto the microwells. The human Follistatin protein in samples is captured by the coated antibody after incubation. Following extensive washing, another antibody of biotinylated specific for human Follistatin is added to detect the captured human Follistatin 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.