Table 2.

Extrapolation of estimated sensitivity and specificity differences applied to a hypothetical cohort of 1000 lesions^a.

		Sensitivitya			Fixed specificityb			Fixed sensitivityb			Specificityc
		True positive, n	False negative, n	False positive, n		True negative, n	True positive, n		False negative, n	False positive, n		True negative, n
10% prevalence		—d	—	180		720	80		20	—		—
	VIe	79	21	—		—	—		—	207		693
	VI + Df	93	7	—		—	—		—	9		891
17% prevalence		—	—	166		664	136		34	—		—
	VI	134	36	—		—	—		—	191		639
	VI + D	158	12	—		—	—		—	8		822
53% prevalence		—	—	94		376	424		106	—		—
	VI	419	111	—		—	—		—	108		362
	VI + D	493	37	—		—	—		—	5		465

^aThe dermoscopy test had a sensitivity of 79%, and the visual inspection and dermoscopy test had a sensitivity of 93%.

^bBoth tests had a fixed specificity and fixed sensitivity of 80%.

^cThe dermoscopy test had a specificity of 77%, and the visual inspection and dermoscopy test had a specificity of 99%.

^dNot applicable.

^eVI: visual inspection.

^fVI + D: visual inspection and dermoscopy.