Table I.

Classification using (a) 200 ng/mL strips (COT200) and (b) 10 ng/mL strips (COT10)

	(a) LC tandem mass spectrometry		(b) LC tandem mass spectrometry
	Total cotinine >200 ng/mL	Total cotinine <200 ng/mL	Total cotinine >10 ng/mL	Total cotinine <10 ng/mL
Test strip positive (%)	199 (49.8)	16 (4)	146 (36.5)	25 (6.3)
Test strip negative (%)	1 (0.25)	184 (46)	2 (0.5)	227 (56.8)
	Sensitivity = 99.5%		Sensitivity = 98.7%
	Specificity = 92.0%		Specificity = 90.1%
	Positive predictive value = 92.6%		Positive predictive value = 85.4%
	Negative predictive value = 99.5%		Negative predictive value = 99.2%
	Accuracy = 95.8%		Accuracy = 93.3%
	n = 400		n = 400
	Agreement between both readers: 99.4%		Agreement between both readers: 97.9%

All tabulated results are from the Primary reader.