Table 2. Hypothetical tests with 80% sensitivity for different proportions of patients in the HR group, showing agranulocytosis risks in the LR group (1-NPV), the HR group (PPV) and specificity of the test.
| Size of HR group | P(A|LR) (1-NPV) | P(A|HR) (PPV) | Specificity |
|---|---|---|---|
| 0.010 | 0.0016 | 0.640 | 0.996 |
| 0.050 | 0.0017 | 0.128 | 0.956 |
| 0.100 | 0.0018 | 0.064 | 0.906 |
| 0.200 | 0.0020 | 0.032 | 0.805 |
| 0.300 | 0.0023 | 0.021 | 0.704 |
| 0.400 | 0.0027 | 0.016 | 0.603 |
| 0.500 | 0.0032 | 0.013 | 0.502 |
Abbreviations: HR, high risk; LR, low risk; NPV, negative predictive value; PPV, positive predictive value.