The Human Procalcitonin ELISA is a sandwich enzyme immunoassay for the quantitative measurement of human procalcitonin. In the Human Procalcitonin ELISA, standards, quality controls and samples are incubated in microplate wells pre-coated with polyclonal anti-human procalcitonin antibody. After 60 minutes incubation and washing, HRP labelled polyclonal anti-human procalcitonin antibody is added and incubated with captured procalcitonin for 60 minutes. After another washing step, the remaining conjugate is allowed to react with the substrate solution (TMB). The reaction is stopped by addition of acidic solution and absorbance of the resulting yellow product is measured. The absorbance is proportional to the concentration of procalcitonin. A standard curve is constructed by plotting absorbance values againstconcentrations of standards, and concentrations of unknown samples are determined using this standard curve.