@article {Zabatierop4228, author = {Juliana Zabatiero and Dem{\'e}tria Kovelis and Mahara Proen{\c c}a and Karina Furlanetto and Leandro Mantoani and Ercy Ramos and F{\'a}bio Pitta}, title = {Optimal cut-off point of exhaled carbon monoxide to validate self-reported smoking status in healthy adults}, volume = {38}, number = {Suppl 55}, elocation-id = {p4228}, year = {2011}, publisher = {European Respiratory Society}, abstract = {Background: There is no current consensus regarding the optimal cut-off point of exhaled carbon monoxide (CO) to distinguish smokers from nonsmokers.Objectives: To assess the accuracy of an exhaled carbon monoxide cut-off point in order to distinguish actual smokers from nonsmokers among apparently healthy adults.Methods: We studied 50 current smokers (20 male; 47{\textpm}12 years; BMI: 26{\textpm}4 kg/m2), with normal lung function (FEV1/FVC: 81{\textpm}6; FEV1: 84{\textpm}18\%pred) who self-reported their smoking status and habits; and 31 paired non-smokers (11 male; 44{\textpm}11 years; BMI: 26{\textpm}4 kg/m2; FEV1/FVC: 83{\textpm}6; FEV1: 102{\textpm}11\%pred). All subjects were submitted to CO assessment (in the group of smokers, after a mean of 10{\textpm}1.2 hours of cigarette abstinence), using a portable CO monitor (MicroCO{\textregistered}).Results: Median [interquartile range] levels of CO in the group of smokers and non-smokers were 10 [7-17] and 3 [2-4], respectively. The 6ppm cut-off point suggested by the manufacturer generated a 77\% sensitivity and 100\% specificity; however a 4.5ppm cut-off point generated the highest combined sensitivity (90\%) and specificity (90\%). The ROC analysis indicated that the CO monitor provided high diagnostic accuracy to distinguish smokers from nonsmokers [area under the curve = 0.979 p\<0,001].Conclusions: Using a portable CO monitor, a 4.5ppm cut-off point seems more accurate than the cut-off point suggested by the manufacturer in order to distinguish smokers from nonsmokers among apparently healthy adults.}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/38/Suppl_55/p4228}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }