title: Possible reasons for elevated carbon monoxide levels in self-reported ex-smokers.
abstract: Expired-air carbon monoxide (CO) is often used to validate self-reported nonsmoking in clinical settings and research studies. It sometimes occurs that a person reports to have quit smoking, whereas the CO measurement classifies him/her as a smoker. This commentary summarizes possible explanations for this discrepancy and briefly discusses what to do when there is reason to believe that the CO measurement is incorrect.
authors.affiliation: Department of General Practice, CAPHRI School for Public Health and Care, Maastricht University Medical Centre, PO Box 616, 6200 MD Maastricht, The Netherlands. d.kotz@maastrichtuniversity.nl
authors.forename: Daniel
authors.initials: D
authors.lastname: Kotz
mesh_terms: D000388:Air / Q000032:analysis*; D001944:Breath Tests; D002248:Carbon Monoxide / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D057566:Self Report; D012680:Sensitivity and Specificity; D012907:Smoking; D016540:Smoking Cessation
chemical_list: D002248:Carbon Monoxide