Table 4.
Performance of the classifier in discovery and validation at three cancer prevalences.
| Dataset | Prevalence (%) | Reference Value | Sensitivity (%) | Specificity (%) | NPV* (%) | PPV (%) |
|---|---|---|---|---|---|---|
| Discovery (n=143) | 15 | 0.60 | 82 | 66 | 95 | 30 |
| 20 | 0.46 | 90 | 49 | 95 | 31 | |
| 25 | 0.42 | 93 | 45 | 95 | 36 | |
|
| ||||||
| Validation (n=104) | 15 | 0.60 | 71 | 44 | 90 | 18 |
| 20 | 0.46 | 83 | 29 | 87 | 23 | |
| 25 | 0.42 | 90 | 27 | 89 | 29 | |
|
| ||||||
| Vanderbilt (n=37) | 15 | 0.60 | 79 | 56 | 94 | 24 |
| 20 | 0.46 | 89 | 33 | 93 | 25 | |
| 25 | 0.42 | 100 | 28 | 100 | 32 | |
The area under the receiver operating characteristic (ROC) curve (AUC) was 0.82, 0.60 and 0.74 in discovery, in validation and for Vanderbilt samples, respectively. Note that partial AUC is the preferred metric for tests maximizing NPV (27).
*
NPV is negative predictive value.
†
PPV is positive predictive value.