title: Time-resolved fluoroimmunoassay compared with virus isolation for rapid detection of respiratory syncytial virus in nasopharyngeal aspirates.
abstract: Two monoclonal antibodies against two distinct conserved epitopes of the respiratory syncytial virus (RSV) nucleocapsid protein were used in a direct time-resolved fluoroimmunoassay (TR-FIA) for the detection of RSV antigens in nasopharyngeal aspirates. The capture antibody was adsorbed to the solid phase of microdilution strip wells, and the indicator antibody was labeled with a europium chelate. Specimens and label were incubated simultaneously for 1 h at 37 degrees C in the coated wells. After the test samples were washed, fluorescence enhancement solution was added, strips were shaken, and the time-resolved fluorescence was measured. The test procedure took only 75 min, and the total time for 20 specimens, with pretreatment by sonication, was 2 to 3 h. We prospectively evaluated the detection of RSV in nasopharyngeal aspirates of pediatric patients by TR-FIA and by virus isolation in human diploid fibroblasts. TR-FIA detected 40 of 42 isolation-positive specimens. Nine additional isolation-negative specimens were positive by TR-FIA; all proved to be true positives by a blocking-type confirmatory assay. The sensitivity, specificity, positive predictive value, and negative predictive value for TR-FIA were 95, 96, 82, and 99%, respectively, of the values obtained by virus isolation and 96, 100, 100, and 99%, respectively, of the values obtained by virus isolation and the confirmatory assay.
authors.affiliation: Department of Virology, University of Turku, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Waris
authors.forename: P
authors.initials: P
authors.lastname: Halonen
authors.forename: T
authors.initials: T
authors.lastname: Ziegler
authors.forename: S
authors.initials: S
authors.lastname: Nikkari
authors.forename: G
authors.initials: G
authors.lastname: Obert
mesh_terms: D000293:Adolescent; D000911:Antibodies, Monoclonal; D002648:Child; D002675:Child, Preschool; D005455:Fluorescent Antibody Technique; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009305:Nasopharynx / Q000382:microbiology*; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification*; D010253:Respirovirus Infections / Q000175:diagnosis*; D013396:Suction; D013997:Time Factors; D014776:Virus Cultivation / Q000379:methods
chemical_list: D000911:Antibodies, Monoclonal