Human IL-6 High Sensitivity ELISA Kit is based on the quantitative sandwich enzyme-linked immunosorbent assay technique to measure concentration of human IL-6 in the samples. A monoclonal antibody specific for human IL-6 has been immobilized onto microwells. Standard or samples are pipetted into the wells, followed by the addition of biotin-linked monoclonal antibody specific for IL-6, and IL-6 present is bound by the immobilized antibody and detect antibody following the first incubation. After removal of any unbound substances, streptavidin-HRP is added for a second incubation. After washing, substrate solution reacts with HRP and color develops in proportion to the amount of IL-6 bound by the immobilized antibody. The color development is stopped by addition of acid and the optical density value is measured by microplate reader.