Table 4 Test performance and number of COVID-19 false positives per 10,000 population tested, for varied test specificities and disease prevalence (given a sensitivity of 99.9%)
Prevalence | Specificity | PPV | False positive rate | Number with disease in population per 10,000 tested | Number of false positives per 10,000 tested |
|---|---|---|---|---|---|
0.0005 | 0.999 | 33.32% | 0.1% | 5 | 10 |
0.0005 | 0.95 | 0.99% | 5.0% | 5 | 500 |
0.0005 | 0.9 | 0.50% | 10.0% | 5 | 1000 |
0.0005 | 0.8 | 0.25% | 20.0% | 5 | 2000 |
0.0005 | 0.7 | 0.17% | 30.0% | 5 | 3000 |
0.001 | 0.999 | 50.00% | 0.1% | 10 | 10 |
0.001 | 0.95 | 1.96% | 5.0% | 10 | 500 |
0.001 | 0.9 | 0.99% | 10.0% | 10 | 1000 |
0.001 | 0.8 | 0.50% | 20.0% | 10 | 2000 |
0.001 | 0.7 | 0.33% | 30.0% | 10 | 3000 |
0.01 | 0.999 | 90.98% | 0.1% | 100 | 10 |
0.01 | 0.95 | 16.79% | 5.0% | 100 | 500 |
0.01 | 0.9 | 9.17% | 10.0% | 100 | 1000 |
0.01 | 0.8 | 4.80% | 20.0% | 100 | 2000 |
0.01 | 0.7 | 3.25% | 30.0% | 100 | 3000 |
0.03 | 0.999 | 96.86% | 0.1% | 300 | 10 |
0.03 | 0.95 | 38.19% | 5.0% | 300 | 500 |
0.03 | 0.9 | 23.60% | 10.0% | 300 | 1000 |
0.03 | 0.8 | 13.38% | 20.0% | 300 | 2000 |
0.03 | 0.7 | 9.34% | 30.0% | 300 | 3000 |