DNA and RNA are damaged by oxidation during aging and in a variety of disease states including cancer. Guanine is the base is most prone to oxidation, and the repair processes initiated to correct the damage release multiple oxidized guanine species into the urine, including 8-hydroxyguanosine (8-OHG), 8-hydroxy-2"-deoxyguanosine (8-OHdG), and 8-hydroxyguanine. Some commercial vendors offer immunoassays that detect only 8-OHdG. Cayman"s DNA/RNA Oxidative Damage (High Sensitivity) ELISA Kit is a competitive assay that can be used to measure 8-OHdG, 8-OHG, and 8-hydroxyguanine. Since the antibody used in the assay recognizes damaged nucleic acid species other than 8-OHdG, the value obtained with our assay will be higher than that obtained by competitor ELISAs or by LC/MS analysis that measure a single species. As such, caution is recommended when comparing results obtained from this kit to those obtained by other methods.