236. Comparison of Nanosphere Verigene® Respiratory Virus Plus and in-house RT-PCR for the near-patient detection of influenza and respiratory syncytial virus (RSV)
Session: Poster Abstract Session: Diagnostics: Virology
Thursday, October 8, 2015
Room: Poster Hall
Posters
  • ID week poster for conference upload.pdf (298.7 kB)
  • Background: Respiratory virus infections are responsible for significant hospital admissions during the winter months, and influenza and RSV are the most commonly identified causes. When bed pressures are high, cohorting of admitted cases is a practical way of balancing patient care against cross-infection, but since clinical presentation can overlap, lab diagnosis has to be accurate to avoid compromising patient segregation. In addition, to safely optimise bed use, accurate testing has also to be performed rapidly after patient presentation and clinical assessment. To this end, we evaluated the Verigene 'RV Plus' platform, which yields rapid diagnostic results in approximately 2.5 hours, against our routine in-house RT-PCR test which can have a turnaround time of up to 24 hours.

    Methods: 103 respiratory samples, previously analysed by the routine in-house multiplex RT-PCR, were retrospectively tested in the Verigene machine as per manufacturer's protocol. Sensitivity, specificity, and analyses of positive/negative predictive values were performed on the Verigene with respect to the in-house test as the gold standard.

    Results: For influenza A, of 43 samples positive by the in-house test, 39 were also positive by Verigene. Of the 4 discordant samples, 2 were indeterminate by Verigene, and 2 had a Ct value of 34 and 36 respectively (in-house PCR cut-off for calling a positive is Ct <36). Sensitivity of the Verigene was 95.1% (95% CI 88.5%-101.7%); specificity was 100% (95% CI 100% - 100%); PPV was 100% (95% CI 100% – 100%) and NPV was 96.9% (95% CI 92.6% – 101.1%).

    For influenza B and RSV, all samples positive by the in-house test were also positive by Verigene. The Verigene additionally identified one sample as influenza B positive, and another as RSV positive, which were both negative by the in-house test.

    Conclusion: The Verigene test provided a rapid and accurate method of identifying influenza and RSV, with a sample to result time of approximately 2.5 hours. This is despite the length of time in storage of the samples before restrospective testing by Verigene - in some cases over 12 months - and which may partly explain the difference in sensitivity between the tests. Optimal situation of the machine would be necessary to provide round-the-clock laboratory results that can benefit both patient and bed management, especially in the winter season when these viruses co-circulate.

    Mike Kidd, PhD FRCPath1, Paul Grant, PhD1, Antonia Underwood, BSc1, Sanjeev Bhadra, BSc2, Shelley Wilson, MSc MBA3 and Vanya Gant, PhD FRCPath4, (1)Clinical Virology, University College London (UCL) Hospitals, London, United Kingdom, (2)Clinical Microbiology, University College London (UCL) Hospitals, London, United Kingdom, (3)Clinical Microbiology & Virology, University College London (UCL) Hospitals, London, United Kingdom, (4)Infection, University College London (UCL) Hospitals, London, United Kingdom

    Disclosures:

    M. Kidd, None

    P. Grant, None

    A. Underwood, None

    S. Bhadra, None

    S. Wilson, None

    V. Gant, None

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