TABLE 2.
Use of PPV and NPV in identification of recent HIV infectionsa
| AI cutoff | Sensitivity (%) | Specificity (%) | Result for indicated PRIb
|
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 5%
|
10%
|
20%
|
40%
|
|||||||
| % PPV | % NPV | % PPV | % NPV | % PPV | % NPV | % PPV | % NPV | |||
| <0.6 | 26.4 | 98.9 | 56.5 | 96.1 | 74.3 | 92.1 | 86.7 | 84.3 | 94.5 | 66.7 |
| <0.7 | 61.8 | 95.1 | 39.0 | 97.8 | 57.9 | 95.7 | 75.6 | 90.9 | 89.5 | 78.9 |
| <0.8 | 79.4 | 92.3 | 35.4 | 98.9 | 52.3 | 97.5 | 71.8 | 94.6 | 86.8 | 86.8 |
| <0.9 | 88.2 | 86.8 | 26.3 | 99.3 | 42.9 | 98.5 | 62.9 | 96.7 | 81.9 | 91.6 |
a
PPV and NPV were calculated for populations with different proportions of recent infections (PRI) and grouped according to AI (sensitivity and specificity are based on the results of the present study).
b
PRI (proportion of recent infections) = (no. of recent infections)/(no. of HIV-positive persons).