title: Interpretation of urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine is adversely affected by methodological inaccuracies when using a commercial ELISA.
abstract: The DNA lesion 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a urinary marker of oxidative stress, is produced from reactions of reactive oxygen species with host DNA 2'-deoxyribonucleotides. The current gold-standard assessment is by complex chromatographic methods using HPLC or LC-MS/MS. Several studies have reported that commercial 8-oxodG ELISA kits correlate sufficiently with chromatographic techniques to be an easier alternative for laboratories without access to gold-standard techniques. However, the assumption that significant correlation translates into a similar ability to differentiate disease categories or treatment groups is yet to be tested. Using LC-MS/MS and two variants of a commercial ELISA, we measured urinary 8-oxodG and creatinine concentrations in young children with cystic fibrosis, a disease associated with oxidative stress, and age-matched controls. We show that, despite significant correlation, both ELISAs overestimate the levels of 8-oxodG, and neither ELISA accurately depicted the difference in group means that was observed by gold-standard LC-MS/MS. The implications of these findings for study outcomes add further support for chromatographic techniques, despite their cost and complexity, to remain the gold standard in urinary 8-oxodG assessment.
authors.affiliation: Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, Perth, WA 6008, Australia. lgarratt@ichr.uwa.edu.au
authors.forename: Luke W
authors.initials: LW
authors.lastname: Garratt
authors.forename: Vilas
authors.initials: V
authors.lastname: Mistry
authors.forename: Rajinder
authors.initials: R
authors.lastname: Singh
authors.forename: Jatinderpal Kaur
authors.initials: JK
authors.lastname: Sandhu
authors.forename: Barbara
authors.initials: B
authors.lastname: Sheil
authors.forename: Marcus S
authors.initials: MS
authors.lastname: Cooke
authors.forename: Peter D
authors.initials: PD
authors.lastname: Sly
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D015415:Biomarkers / Q000652:urine; D002648:Child; D002675:Child, Preschool; D002853:Chromatography, Liquid / Q000379:methods; D003550:Cystic Fibrosis / Q000652:urine; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000276:immunology / Q000652:urine; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018384:Oxidative Stress; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D015415:Biomarkers; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine