title: Urea, the most abundant component in urine, cross-reacts with a commercial 8-OH-dG ELISA kit and contributes to overestimation of urinary 8-OH-dG.
abstract: Urinary 8-OH-dG is commonly analyzed as a marker of oxidative stress. For its analysis, ELISA and HPLC methods are generally used, although discrepancies in the data obtained by these methods have often been discussed. To clarify this problem, we fractionated human urine by reverse-phase HPLC and assayed each fraction by the ELISA method. In addition to the 8-OH-dG fraction, a positive reaction was observed in the first eluted fraction. The components in this fraction were examined by the ELISA. Urea was found to be the responsible component in this fraction. Urea is present in high concentrations in the urine of mice, rats, and humans, and its level is influenced by many factors. Therefore, certain improvements, such as a correction based on urea content or urease treatment, are required for the accurate analysis of urinary 8-OH-dG by the ELISA method. In addition, performance of the ELISA at 4 degrees C reduced the recognition of urea considerably and improved the 8-OH-dG analysis.
authors.affiliation: Department of Environmental Oncology, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
authors.forename: Ming-Fen
authors.initials: MF
authors.lastname: Song
authors.forename: Yun-Shan
authors.initials: YS
authors.lastname: Li
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ootsuyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kasai
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Kawai
authors.forename: Masanori
authors.initials: M
authors.lastname: Ohta
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Eguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamato
authors.forename: Yuki
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Rie
authors.initials: R
authors.lastname: Yoshida
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Ogawa
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D015415:Biomarkers / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000276:immunology / Q000652:urine; D003951:Diagnostic Errors; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D011933:Reagent Kits, Diagnostic; D013696:Temperature; D014508:Urea / Q000276:immunology* / Q000652:urine
chemical_list: D015415:Biomarkers; D011933:Reagent Kits, Diagnostic; D000080242:8-Hydroxy-2'-Deoxyguanosine; D014508:Urea; D003849:Deoxyguanosine