Evaluation of five methods for respiratory syncytial virus detection

A total of 117 nasal aspirates were cultured for respiratory syncytial virus (RSV) and tested for RSV antigen by a direct fluorescent-antibody (DFA) test (Bartels Immunodiagnostic Supplies, Inc., Bellevue, Wash.), the Directigen enzyme immunoassay (EIA; Becton Dickinson Microbiology Systems, Cockeysville, Md.), the TestPack EIA (Abbott Laboratories, North Chicago, Ill.), and RSV EIA (Abbott). Agreement of two of five methods or a positive RSV culture were required to validate a result. A total of 57 of 117 (48.7%) specimens were culture positive in HEp-2 cells, A549 cells, or both. A total of 5 of 117 (4.3%) additional specimens met the criteria of a positive specimen; i.e., 62 of 117 (53.0%) specimens were positive. Results obtained from 77 of 117 (65.8%) specimens were concordant for all five methods. The sensitivities, specificities, and positive and negative predictive values for the culture and DFA methods were 91.9, 100, 100, and 91.7% and 91.9, 96.4, 96.6, and 91.4%, respectively. The sensitivities, specificities, and positive and negative predictive values for the three EIA procedures, Directigen, TestPack, and RSV EIA, were 75.8, 80.0, 81.0, and 74.6%; 93.6, 100, 100, and 93.2%; and 71.0, 100, 100, and 75.3%, respectively. New self-contained EIA configurations and the DFA method offer attractive alternatives to the culture method. Technical simplicity, rapid turnaround time, performance, and cost must all be considered when selecting a system for RSV detection.