Clinical evaluation of radioimmunoassay of nasopharyngeal secretions and serology for diagnosis of viral infections in children hospitalized for respiratory infections.

Viral diagnosis was performed using radioimmunoassay (RIA) for virus antigen in nasopharyngeal secretions (NPS) and complement-fixation (CF) tests of paired sera from specimens of 90 children hospitalized for acute respiratory infection. Major respiratory viruses sought for by both methods (adenoviruses, influenza A and B viruses, parainfluenza virus type 3, respiratory syncytial virus) were detected in 40 (44%) of the patients; 15% of the diagnoses were made by NPS-RIA alone. Serologic diagnosis of other viral infections was confirmed in six additional cases. In the different clinical entities a viral diagnosis was established as follows: pneumonia, 50%; upper or middle respiratory infection with no wheezing, 43%; acute laryngitis, 54%; and wheezing bronchitis, 29%. In each clinical entity the virus-positive and virus-negative patients had similar total leukocyte counts, mean C-reactive protein levels and mean erythrocyte sedimentation rates. There was no difference in the duration of hospitalization between the patients with positive and negative viral studies. It was not possible to divide the patients into clinical subgroups according to the presence or absence of detectable viral infection.