Table 2.
Predictive values |
Distribution of test outcomes among 10 000 people tested |
|||||
---|---|---|---|---|---|---|
PPV | NPV | True positive | False positive | True negative | False negative | |
25% likelihood of testing positive | ||||||
80% sensitivity, 97% specificity | 90% | 94% | 2000 | 225 | 7275 | 500 |
80% sensitivity, 98% specificity | 93% | 94% | 2000 | 150 | 7350 | 500 |
80% sensitivity, 99% specificity | 96% | 94% | 2000 | 75 | 7425 | 500 |
90% sensitivity, 99% specificity | 97% | 97% | 2250 | 75 | 7425 | 250 |
50% likelihood of testing positive | ||||||
80% sensitivity, 97% specificity | 96% | 83% | 4000 | 150 | 4850 | 1000* |
80% sensitivity, 98% specificity | 98% | 83% | 4000 | 100 | 4900 | 1000* |
80% sensitivity, 99% specificity | 99% | 83% | 4000 | 50 | 4950 | 1000* |
90% sensitivity, 99% specificity | 99% | 91% | 4500 | 50 | 4950 | 500 |
People presenting for care or at testing centres. NPV=negative predictive value. PPV=positive predictive value.
Mitigation strategy is to confirm negatives.