8-hydroxy-2'-deoxyguanosine (8-OHdG) is an oxidized derivative of deoxyguanosine. Concentrations of 8-oxo-dG within a cell are a measurement of oxidative stress. It is considered as a critical biomarker of oxidative stress and carcinogenesis. This ELISA kit uses Competitive-ELISA as the method. The microtiter plate provided in this kit has been pre-coated with 8-OHdG. During the reaction,8-OHdG in the sample or standard competes with a fixed amount of 8-OHdG on the solid phase supporter for sites on the Biotinylated Detection Antibody specific to 8-OHdG. The concentration of 8-OHdG in the samples is determined by comparing the O.D. of the samples to the standard curve.