Diagnostic testing for community-acquired pneumonia

The clinical, radiographic, and routine laboratory features of community-ac quired pneumonia can offer clues to the microbial cause of the infection, b ut a specific etiologic diagnosis requires the assistance of the microbiolo gy laboratory. This article reviews the methods currently available for the microbiologic diagnosis of lower respiratory tract infection, including ne w methods for rapid diagnosis that are just entering the clinical laborator y. The role of invasive procedures in specimen procurement also is examined . Finally, the diagnostic challenges offered by specific common pathogens a re considered in detail. By carefully evaluating the yields and limitations of the available tests, a reasonable approach to the diagnostic evaluation of the patient with community-acquired pneumonia can be formulated.