SimulFluor respiratory screen for rapid detection of multiple respiratory viruses in clinical specimens by immunofluorescence staining

A new rapid direct immunofluorescence assay (DFA) respiratory screen reagent for detection of seven common respiratory viruses (respiratory syncytial virus [RSV], influenza A and B viruses, parainfluenza virus types 1 to 3, and adenovirus) was compared with standard single or dual DFA reagents and culture. In total, 1,531 respiratory samples were adequate for testing with both SimulFluor Respiratory Screen (RS) reagent (Chemicon International, Temecula, Calif.) and single or dual DFA reagents. The RS DFA reagent detected 367 (98.4%) and single or dual DFA reagents detected 368 (98.7%) of 373 DFA-positive samples. In addition, the RS DFA reagent was equivalent to or better than culture for detection of all viruses except adenovirus. Only 15 of 799 (1.9%) RS-negative samples inoculated into cell cultures yielded respiratory virus isolates (one RSV, five influenza A virus, two influenza B virus, one parainfluenza virus, and six adenovirus). Sixty-six other virus isolates (13 rhinovirus, 24 cytomegalovirus, 28 herpes simplex virus type 1, and 1 enterovirus) were also recovered in culture. With cytospin preparation of slides, only 7.5% of samples submitted were deemed inadequate for DFA. The availability of a rapid DFA screening reagent for detection of multiple common respiratory viruses within 1 to 2 h of sample collection should be of great benefit in terms of patient management and infection control.