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

Abstract

For detection of respiratory syncytial virus (RSV), the BD Directigen RSV rapid antigen assay was compared to Cepheid's real-time reverse transcriptase PCR RSV analyte-specific reagents. The Directigen RSV assay resulted in a 23% false-negative rate, using PCR and chart review as the gold standard, indicating that rapid RSV PCR results would be advantageous.Rapid detection of respiratory viruses is important for many reasons, including prevention of unnecessary antibiotic use, identification of individuals who can benefit from antivirals, and improvement of infection control by grouping individuals with the same viral infection. Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in young children (17). Three percent of all children are hospitalized with bronchiolitis in the first year of life, and RSV is the most common cause of this hospitalization (2). An estimated 50% of all children are infected with RSV during the first year of life, and by 3 years of age, 100% have experienced at least one infection (14). Since RSV infection does not induce protective immunity, reinfection is common.Diagnosis of RSV infection can be made by observation of clinical signs and symptoms, characteristic chest radiographs, rapid antigen detection, viral culture, or reverse transcriptase PCR (RT-PCR) of nasopharyngeal (NP) specimens (2). 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). In this study, we compared assays using Cepheid's RSV analyte-specific reagents (ASR) to the BD Directigen RSV rapid antigen assay (BD Diagnostics, Sparks, MD).Respiratory specimens (n ϭ 142) consisting of NP aspirates (n ϭ 140) and NP swabs (n ϭ 2) from the 2005-2006 peak season were initially tested for RSV by the rapid antigen assay, following the manufacturer's protocol. The samples were put into 2 ml of viral transport media prior to being tested; for NP aspirates, the entire volume received was inoculated. These specimens were from patients ranging from 3 days to 74 years of age. Sixty-eight percent (n ϭ 96) of the specimens were from infants (less than 1 year of age), 21% (n ϭ 30) from individuals between 1 and 5 years of age, and 11% (n ϭ 16) from individuals who were greater than 5 years of age. By the rapid antigen assay, 34% (n ϭ 48) of the specimens were RSV positive. Of the positives, 81% (n ϭ 39) were from individuals less than 1 year of age, 13% (n ϭ 6) from individuals 1 to 5 years of ag...

Comparison of Viral Isolation and Multiplex Real-Time Reverse Transcription-PCR for Confirmation of Respiratory Syncytial Virus and Influenza Virus Detection by Antigen Immunoassays

“…The improved sensitivity of PCR over antigen testing and virus isolation for RSV (14,16,44,45) and influenza virus (17,20,40,41,48) has been previously demonstrated by uniplex, as well as multiplex, testing (4,23,28,32). Studies have also demonstrated improved sensitivity of PCR in combination with culture as a composite "gold standard" or as the alternate reference test for RSV or influenza virus (1,19,33,36,38).…”

“…Studies have also demonstrated improved sensitivity of PCR in combination with culture as a composite "gold standard" or as the alternate reference test for RSV or influenza virus (1,19,33,36,38). A very small minority of previous studies evaluating PCR detection of influenza virus and RSV have included controls to monitor inhibition due to inadequate extraction and purification of nucleic acids (16,23,28,36). Estimates of sensitivity are incomplete or compromised without the inclusion of an internal control to monitor these potential false-negative results.…”

Detection of respiratory syncytial virus using nanoparticle amplified immuno-polymerase chain reaction

“…To date, one of the most sensitive diagnostics available for the detection of RSV has been the use of Reverse Transcription Polymerase Chain Reaction (RTPCR) to amplify and detect RSV genetic material [19] and [20]. However, detection of the negative-sense RNA genome or mRNA of the virus comes with a few drawbacks.…”

Evaluation of the Cepheid Respiratory Syncytial Virus and Influenza Virus A/B real-time PCR analyte specific reagent

“…However it is not feasible to provide urgent out of hours testing based on this multiplex format therefore alternative virus specific testing is preferable for urgent individual samples. A rapid, real-time PCR-based diagnostic test for RSV and influenza A and B which can be performed in a relatively short turn around time would be extremely useful for patient management (Goodrich and Miller, 2007). In addition, the resulting improved treatment of patients presenting with respiratory illness would help infection 0166-0934/$ -see front matter © 2009 Elsevier B.V. All rights reserved.…”