title: Epidemiological marker for oxidant status: comparison of the ELISA and the gas chromatography/mass spectrometry assay for urine 2,3-dinor-5,6-dihydro-15-F2t-isoprostane.
abstract: OBJECTIVE
  A biomarker of oxidant status applicable to epidemiological research is essential to studying the relationship between free radicals and chronic disease risk. Gas chromatography with mass-spectrometry detection (GC/MS) is the gold standard for measurement of urinary F2-isoprostanes (F2-isoPs), a non-invasive marker of oxidant status. However, this method is laborious and costly, which prohibits its use in large epidemiological studies.
  
  
  METHODS
  We compared GC/MS assay with an inexpensive quick enzyme-linked immunoassay (ELISA) in measurements of 2,3-dinor-5,6-dihydro-15-F2t-isoprostane (F2-isoPM), an abundant beta-oxidation metabolite of 8-iso-prostaglandin-F2alpha. We measured F2-isoPM in urine of 52 participants of the Insulin Resistance Atherosclerosis Study by both methods.
  
  
  RESULTS
  The ELISA measurements showed approximately 30-fold greater mean and median (22.10, SD 12.92, and 18.49 ng/mg creatinine) than the GC/MS measurements (0.703, SD 0.468, and 0.597 ng/mg creatinine). We found low linear correlation (Pearson correlation coefficient 0.51; 95% CI, 0.28-0.70) and weak agreement in ranking subjects by tertiles (weighted Kappa statistic 0.34) between a GC/MS and ELISA.
  
  
  CONCLUSIONS
  We conclude that the current ELISA method is not a valid substitute for the GS/MS assay.
authors.affiliation: Wake Forest University School of Medicine, Departments of Cancer Biology and Public Health Sciences, Winston-Salem, NC 27157, USA. dilyasov@wfubmc.edu
authors.forename: Dora
authors.initials: D
authors.lastname: Il'yasova
authors.forename: Jason D
authors.initials: JD
authors.lastname: Morrow
authors.forename: Anastasia
authors.initials: A
authors.lastname: Ivanova
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Wagenknecht
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000652:urine*; D015992:Body Mass Index; D004797:Enzyme-Linked Immunosorbent Assay; D004812:Epidemiologic Methods; D028441:F2-Isoprostanes / Q000652:urine*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000652:urine*
chemical_list: D015415:Biomarkers; D028441:F2-Isoprostanes