Prospective evaluation of a dot-blot enzyme immunoassay (Directigen RSV) for the antigenic detection of respiratory syncytial virus from nasopharyngeal aspirates of paediatric patients

This study investigated the efficacy of a commercial enzyme immunoassay (Directigen RSV, ColorPAC) in comparison with the shell vial culture method (using Hep-2 cells) for the detection of respiratory syncytial virus (RSV) in nasopharyngeal aspirates from children with bronchiolitis. During the period 1995-2002, 4950 samples were examined. RSV was detected in 1660 (33.5%) samples, with a sensitivity of 80.9%, a specificity of 97.5%, a positive predictive value of 93.8%, a negative predictive value of 91.6%, and a testing efficiency value of 92.2% compared with shell vial culture. In 83 (5%) samples, the ColorPAC was positive and the shell vial assay was negative. Of these, 71 (85.6%) were false-negative by cell culture. The true false-positive results obtained by ColorPAC represented only 0.7% of all RSV-positive samples. In general, no statistically significant differences were detected between the different months and epidemic periods studied. Compared with ColorPAC, the shell vial culture method displayed a sensitivity of 95.8% and a specificity of 100%. Overall, the ColorPAC assay was an acceptable, simple and rapid method for the antigenic detection of RSV in paediatric respiratory samples.