Table 4.

ROC analyses for the optimal urine NNAL cutoff point using different urine cotinine criteria for active smoking

Positive cotinine cutoffAUCCutoff pointNoted forSensitivitySpecificityYouden
Volume based—NNAL pg/mL
Cotinine > 10 ng/mL0.9176.2Equality0.8720.8730.743
6.6Youden0.8720.8860.758
Cotinine > 15 ng/mL0.9428.2Equality0.8840.8840.768
15.5Youden0.8410.9490.790
Cotinine > 20 ng/mL0.95513.9Equality0.9310.9310.862
15.5Youden0.9310.9410.872
Cotinine > 30 ng/mL0.97114.4Equality, Youden0.9460.9340.882
Creatinine adjusted—NNAL (pg/mg creatinine)
Cotinine > 10 ng/mL0.9294.1Equality0.8700.8700.740
5.6Youden0.8570.9170.774
Cotinine > 15 ng/mL0.9605.7Equality0.9120.9110.822
6.6Youden0.9120.9240.836
Cotinine > 20 ng/mL0.9718.5Equality0.930.9210.851
6.6Youden0.9650.9080.873
Cotinine > 30 ng/mL0.97210.2Equality0.9260.9270.853
6.6Youden0.9810.9040.885