Fig. 2From: Exposure to prenatal secondhand smoke and early neurodevelopment: Mothers and Children’s Environmental Health (MOCEH) studyROC curve analysis of urinary cotinine levels for differentiating current smokers from nonsmokers. The optimal urine cotinine cut-off level to distinguish active smokers from non-active smokers was 42.7 ng/ml, with sensitivity of 81.8% and specificity of 96.5%. The area under the curve (AUC) was 0.91Back to article page