Table 6. Summary of PPV and NPV for two-stratum and four-stratum test.
| Dataset | Two-stratum test |
Four-stratum test |
|||||
|---|---|---|---|---|---|---|---|
| Positive PPV | Negative NPV | High positive PPV | Positive PPV | Negative NPV | Low negative NPV | ||
| Set A | 10.9% (1 in 9) | 1.8% (1 in 57) | 27.4% (1 in 4) | 5.5% (1 in 18) | 2.0% (1 in 49) | 1.0% (1 in 105) | |
| Set B | 7.6% (1 in 13) | 2.1% (1 in 47) | 11.3% (1 in 9) | 5.4% (1 in 19) | 2.3% (1 in 43) | 1.5% (1 in 65) | |
| Set C | 10.3% (1 in 10) | 1.9% (1 in 53) | 22.6% (1 in 4) | 6.3% (1 in 16) | 2.1% (1 in 47) | 1.5% (1 in 67) | |
| Combined | 9.4% (1 in 11) | 2.0% (1 in 51) | 19.3% (1 in 5) | 5.4% (1 in 18) | 2.3% (1 in 43) | 1.1% (1 in 90) | |
PPV, positive predictive value; NPV, negative predictive value, in its reciprocal form, i.e., 1-NPV. Based on a population lung cancer prevalence of 2.7%.