Box 1 | Dependence of PPV on prevalence
From the following article:
Evaluation of diagnostic tests for infectious diseases: general principles
Shabir Banoo, David Bell, Patrick Bossuyt, Alan Herring, David Mabey, Freddie Poole, Peter G Smith, N. Sriram, Chansuda Wongsrichanalai, Ralf Linke, Rick O'Brien, Mark Perkins, Jane Cunningham, Precious Matsoso, Carl Michael Nathanson, Piero Olliaro, Rosanna W. Peeling & Andy Ramsay
Nature Reviews Microbiology 5, S21-S31 (November 2007)
doi:10.1038/nrmicro1523
The positive predictive value (PPV) of a test will depend not only on the sensitivity of the test but also on the prevalence of the condition within the population being tested. The figure below shows how the positive predictive value for a test with 96% sensitivity varies according to the prevalence of infection in the population.
