Selected volatile organic compounds as biomarkers for exposure to tobacco smoke.

Cutoff levels on the scales for benzene, ethylbenzene, toluene, styrene, o-xylene and m/p-xylene in blood were developed to classify smokers from non-smokers. Self-reported smoking during the last 5 d was used as the true smoking status. Receiver operating characteristics methods that minimized the difference between specificity and sensitivity were used to develop these cutoffs. Data from National Health and Nutrition Examination Survey for the cycle 2005-2006 were used for this purpose. For the total population, a cutoff of 0.038 ng/ml for benzene was able to classify smokers from non-smokers with a sensitivity of 83.6% and specificity of 83.7%.