Table 4.

Relationship between test performance, PPV, and NPV in the general asymptomatic population

	Predictive values		Distribution of test outcomes among 10 000 people tested
	PPV	NPV	True positive	False positive	True negative	False negative
1% likelihood of testing positive
80% sensitivity, 97% specificity	21%	100%	80	297*	9603	20
80% sensitivity, 98% specificity	29%	100%	80	198*	9702	20
80% sensitivity, 99% specificity	45%	100%	80	99*	9801	20
90% sensitivity, 99% specificity	48%	100%	90	99*	9801	10
2·5% likelihood of testing positive
80% sensitivity, 97% specificity	41%	99%	200	293*	9458	50
80% sensitivity, 98% specificity	51%	99%	200	195*	9555	50
80% sensitivity, 99% specificity	67%	99%	200	98	9653	50
90% sensitivity, 99% specificity	70%	100%	225	98	9653	25

NPV=negative predictive value. PPV=positive predictive value.

^*Mitigation strategy is to confirm all positives.