Roy P Zuurbier, Koos Korsten, Theo J M Verheij, Chris Butler, Niels Adriaenssens, Samuel Coenen, Olivier Gruselle, Valerie Vantomme, Marlies A van Houten, Louis J Bont, Joanne G Wildenbeest, REspiratory Syncytial Virus Consortium in EUrope (RESCEU) Investigators
Respiratory syncytial virus (RSV) causes a substantial burden in older adults. Viral load in RSV-infected adults is generally lower compared to young children, which could result in suboptimal sensitivity of RSV diagnostics. Although the Xpert® Xpress Flu/RSV assay has been used in routine clinical care, its sensitivity to diagnose RSV infection in older adults is largely unknown. We aimed to compare the performance of the Xpert® Xpress Flu/RSV assay with real-time reverse-transcription polymerase chain reaction (RT-PCR) in home-dwelling older adults (≥60 years of age).
Nasopharyngeal swabs were tested with Xpert® Xpress Flu/RSV and compared to RSV RT-PCR in older adults with acute respiratory tract infections with different levels of disease severity.
We studied 758 respiratory samples from 561 older adults from 2 consecutive RSV seasons. Thirty-five (4.6%) samples tested positive for RSV by at least 1 of the assays, of which 2 samples were negative by Xpert® Xpress Flu/RSV and 3 samples by real-time RT-PCR. The positive percentage agreement (PPA) was 90.9% (95% confidence interval [CI], 76.4%–96.8%) and negative percentage agreement was 99.7% (95% CI, 99.0%–99.9%). Viral loads were low (≤103 copies/mL or cycle threshold value ≥34) in all cases with discordant results for the 2 assays.
The PPA of Xpert® Xpress Flu/RSV compared to routine RT-PCR is high for RSV detection in home-dwelling older adults. The assay is fast and easy to use at the point of care.
Keywords: Respiratory syncytial virus, diagnosis, molecular, point-of-care test, older adults
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