Table 2.

Comparisons of performance between GC, EMIT and NicAlert

a)
NicAlert Scale	Expected cotinine value	# of samples present	# of samples expected	GC results of samples present in range
0	0–10 ng/mL	1	14	0 (n/a)
1	10–30 ng/mL	12	3	2.2 (1.8)
2	30–100 ng/mL	4	4	28.6 (18.0)
3	100–200 ng/mL	1	0	204 (n/a)
4	200–500 ng/mL	0	10	n/a
5	500–1000 ng/mL	8	8	268.1 (110.0)
6	>1000 ng/mL	22	9	923.2 (115.3)

b)
	True positive	True negative	False positive	False negative	Specificity (95% CI)	Sensitivity (95% CI)	Positive predictive value (95% CI)	Negative predictive value (95% CI)
NicAlert vs. GC	32	16	1	1	94% (69%–100%)	97% (82%–100%)	97% (82%–100%)	94% (69%–100%)
EMIT vs. GC	30	17	0	3	100% (77%–100%)	91% (75%–98%)	100% (85%–100%)	85% (61%–96%)

a) Semi-quantitative comparisions between NicAlert and GC. The two samples where observers did not agree on the NicAlert result have been removed. Expected cotinine value ranges are provided by the manufacturer. The number of samples expected is based on how many samples would be expected to fall into that range based on GC results. GC cotinine results are listed as mean (standard error).

b) Comparisons of accuracy in determining smoking status between EMIT and NicAlert. Note. CI, confidence interval.