AT III ELISA kit applies the competitive enzyme immunoassay technique utilizing a monoclonal anti-AT III antibody and an AT III-HRP conjugate. The assay sample and buffer are incubated together with AT III-HRP conjugate in pre-coated plate for one hour. After the incubation period, the wells are decanted and washed five times. The wells are then incubated with a substrate for HRP enzyme. The product of the enzyme-substrate reaction forms a blue colored complex. Finally, a stop solution is added