Table 2

2×2 Table with changing predictive values dependent on prevalence

Disease+Disease−
Higher prevalence (5%) with 99% sensitive and 95% specific rapid HIV test
Test+495475
Test−59025
PPV: 51%
Lower prevalence (1%) with 99% sensitive and 95% specific rapid HIV test
Test+99495
Test−19405
PPV: 16.7%
  • PPV, positive predictive value.