Diagnosis of viral pneumonia.

The diagnosis of viral pneumonia has changed during the past decade from a purely clinical diagnosis to one that is both clinical and laboratory in nature. Viral pneumonias can be divided into two clinical groups: the so-called "atypical" pneumonias in otherwise normal hosts, and viral pneumonitis in the immunocompromised host. Clinical factors such as patient age, immune status, time of year, illness in other family members, community outbreaks, onset, severity, duration of symptoms, and the presence of a rash remain important aids in diagnosing viral causes of both atypical pneumonia and pneumonia in the immunocompromised patient. However, advances in virus culture methodologies and the use of monoclonal antibodies coupled with immunofluorescence and ELISA techniques have markedly enhanced both the sensitivity, specificity, and rapidity of the diagnosis of viral pneumonias. Further advances are expected in the future as nucleic acid hybridization techniques are increasingly applied to both viral cultures and direct analysis of clinical specimens.