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.
A. Underwood, None
S. Bhadra, None
S. Wilson, None
V. Gant, None