Table 4.
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.