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

Abstract

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.

Performance of indirect immunofluorescence assay, immunochromatography assay and reverse transcription-polymerase chain reaction for detecting human respiratory syncytial virus in nasopharyngeal aspirate samples

“…In addition, other studies conducted on larger numbers of pediatric specimens using rapid ICA yielded relative indices for sensitivity ranging from 71.0% to 89.2% (Aldous et al 2004, Reina et al 2004, Zheng et al 2004, which agree with the findings of the present study.…”

“…Neither blood contamination nor high viscosity was observed in these samples, and no other cross reactivity-inducing factors in ICA-BD could be elucidated. By using an immunomembrane filter-based rapid test, Reina et al (2004) found that 0.25% of all samples (representing 0.7% of HRSV-positive NPA) were true false-positives. On the other hand, two samples that were tested negative by RT-PCR were tested positive by both IFA and ICA-BD, presumably due to inhibition of polymerization during PCR process- ing.…”

“…Human respiratory syncytial virus (HRSV) is the major cause of severe lower respiratory tract disease in children (Law et al 2002, Simoes & Carbonell-Estrany 2003, Reina et al 2004, and been most severe in premature infants and those with congenital immunodeficiency, heart disease and/or bronchopulmonary dysplasia (Welliver 2003). According to WHO (2003), HRSV is responsible for 160,000 deaths per year.…”

“…However, this technique requires adequate equipment and highly trained technicians in order to obtain accurate results. Enzyme immunoassays and molecular based techniques such as reverse transcription-polymerase chain reaction (RT-PCR) have been shown to be useful in detecting respiratory viruses in a clinical setting (Dayan et al 2002, Falsey et al 2002, 2003, Reina et al 2004, Shirato et al 2007. Rapid test kits are also commercially available for detecting specific respiratory viruses such as influenza A&B and HRSV (Krilov et al 1994).…”

Comparison of Cepheid's Analyte-Specific Reagents with BD Directigen for Detection of Respiratory Syncytial Virus

“…The most common laboratory method for rapid detection of RSV includes rapid antigen (enzyme immunoassay) assays produced by multiple manufacturers, with various sensitivities of 57 to 98% and specificities between 70 and 100% (1,5,10,11,13,16,20). Other diagnostic tests include culture (routine tissue culture and shell vial culture), with sensitivities between 70 and 80% and specificities of 100% (10,11,19), and direct fluorescent antigen detection, with sensitivities between 93 and 100% and specificities of 95 to 100% (1,10,16). More recently, real-time RT-PCR assays have been described as demonstrating sensitivities of 73 to 97% and specificities of 64 to 99% (7,9,11).…”