What diagnostic tests are needed for community-acquired pneumonia?

Diagnostic tests are used to confirm the presence of community-acquired pne umonia (CAP), assess severity, and identify the responsible pathogen. At pr esent, there is no study or combination of studies that can consistently pr ovide a microbiologic diagnosis, and controversy continues as to what tests should be performed. This article reviews each of the roles of diagnostic testing in CAP and focuses on the issue of microbiologic diagnosis. Based o n available evidence, recommendations are provided for use of diagnostic st udies in CAP.