Laboratory diagnosis of respiratory infections

The laboratory diagnosis of infections of the respiratory tract is not an e xact science, with many clinicians electing to empirically select antimicro bial therapy without the benefit of laboratory testing. With trained labora tory personnel and the proper selection of tests, accurate laboratory diagn osis is available. Progress is occurring most rapidly with molecular method s, such as polymerase chain reaction (PCR) testing. As molecular approaches are technically simplified and become less expensive, advances in the labo ratory diagnosis of most respiratory tract infections caused by fastidious pathogens will occur. The diagnosis of non-fastidious bacteria, that requir e in-vitro antimicrobial testing, will continue to require conventional cul ture methods. New bronchoscopic methods, quantitative evaluation of culture s, and recognition of intracellular bacteria in stained smears do improve t he usefulness of conventional culture and stain in the diagnosis of pneumon ia. Curr Opin infect Dis 12:115-119. (C) 1999 Lippincott Williams & Wilkins .