are recognized as a list of active molecules, such as O2•−, 1O2, H2O2 and, •OH . A nucleic acid can be oxidized by ROS through a Fenton reaction. To date, around 20 oxidative lesions have been discovered in DNA. RNAs are likely to be more sensitive to ROS for the following reasons: i) the basically single-stranded structure exposes more sites to ROS; ii) compared with nuclear DNA, RNAs are less compartmentalized; iii) RNAs distribute broadly in cells not only in the nucleus as DNAs do, but also in large portions in the cytoplasm. This theory has been supported by a series of discoveries from rat livers, human leukocytes, etc. Actually, monitoring a system by applying the isotopical label [18O]-H2O2 shows greater oxidation in cellular RNA than in DNA. Oxidation randomly damages RNAs, and each attack bring problems to the normal cellular metabolism. Although alteration of genetic information on mRNA is relatively rare, oxidation on mRNAs in vitro and in vivo results in low translation efficiency and aberrant protein products. Though the oxidation strikes the nucleic strands randomly, particular residues are more susceptible to ROS, such hotspot sites being hit by ROS at a high rate. Among all the lesions discovered thus far, one of the most abundant in DNA and RNA is the 8-hydroxyguanine. Moreover, 8-hydroxyguanine is the only one measurable among all the RNA lesions. Besides its abundance, 8-hydroxydeoxyguanosine (8-oxodG) and 8-hydroxyguanosine (8-oxoG) are identified as the most detrimental oxidation lesions for their mutagenic effect, in which this non-canonical counterpart can faultily pair with both adenine and cytosine at the same efficiency. This mis-pairing brings about the alteration of genetic information through the synthesis of DNA and RNA. In RNA, oxidation levels are mainly estimated through 8-oxoG-based assays. So far, approaches developed to directly measure 8-oxoG level include HPLC-based analysis and assays employing monoclonal anti-8-oxoG antibody. The HPLC-based method measures 8-oxoG with an electrochemical detector (ECD) and total G with a UV detector. The ratio that results from comparing the two numbers provides the extent that the total G is oxidized. Monoclonal anti-8-oxoG mouse antibody is broadly applied to directly detect this residue on either tissue sections or membrane, offering a more visual way to study its distribution in tissues and in discrete subsets of DNA or RNA. The established indirect techniques are mainly grounded on this lesion’s mutagenic aftermath, such as the lacZ assay. This method was first