In this assay the
CRP present in samples reacts with the anti-CRP antibodies which have been adsorbed to the
surface of polystyrene microtiter wells. After the removal of unbound proteins by washing, antiCRP antibodies conjugated with horseradish peroxidase (HRP) are added. These enzymelabeled antibodies form complexes with the previously bound CRP. Following another washing
step, the bound enzyme is assayed by the addition of a chromogenic substrate, 3,3’,5,5’-
tetramethylbenzidine (TMB). The quantity of bound enzyme varies directly with the concentration
of CRP in the sample tested; thus, the absorbance, at 450 nm, is a measure of the concentration
of CRP in the test sample. The quantity of CRP in the test sample can be interpolated from the
standard curve constructed from the standards and corrected for sample dilution.