Clinical Evaluation of Xpert Xpress CoV-2/Flu/RSV <i>plus</i> and Alinity m Resp-4-Plex Assay

The performance of the Xpert Xpress CoV-2/Flu/RSV <i>plus</i> and Alinity m Resp-4-Plex Assays were evaluated using 167 specimens, including 158 human respiratory specimens and 9 external quality assessment program (EQAP) samples. For respiratory specimens, CoV-2/Flu/RSV <i>plus<...

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Main Authors: Wai-Sing Chan, Kan-Pui Wong, Siu-Kei Yau, Ching-Yan Wong, Tsz-Ching Chan, Jeffrey Hung, Kristi Tsz-Wan Lai, Chin-Pang Leung, Candy Ling-Na Wang, Chun-Hang Au, Thomas Shek-Kong Wan, Edmond Shiu-Kwan Ma, Bone Siu-Fai Tang
Format: Article
Language:English
Published: MDPI AG 2024-03-01
Series:Diagnostics
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Online Access:https://www.mdpi.com/2075-4418/14/7/683
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Summary:The performance of the Xpert Xpress CoV-2/Flu/RSV <i>plus</i> and Alinity m Resp-4-Plex Assays were evaluated using 167 specimens, including 158 human respiratory specimens and 9 external quality assessment program (EQAP) samples. For respiratory specimens, CoV-2/Flu/RSV <i>plus</i> exhibited perfect agreement with the standard-of-care (SOC) methods (Cohen’s κ: 1, 100% agreement). The overall positive and negative percent agreement (PPA and NPA) were 100%, with 95% confidence intervals of 96.50 to 100% and 85.70 to 100%, respectively. On the other hand, Resp-4-Plex revealed an almost perfect agreement with the SOC methods (Cohen’s κ: 0.92, 97.71% agreement). The overall PPA and NPA were 100% (95.76 to 100%) and 88.46% (70.20 to 96.82%), respectively. For EQAP samples, the results of CoV-2/Flu/RSV <i>plus</i> (9/9) and Resp-4-Plex (4/4) were concordant with the expected results. The experimental limit of detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the lowest (25 copies/mL for both methods), and that of the respiratory syncytial virus was the highest (400 copies/mL for CoV-2/Flu/RSV <i>plus</i> and 100 copies/mL for Resp-4-Plex). Threshold cycle (Ct) value correlation showed a large positive linear association between CoV-2/Flu/RSV <i>plus</i> and Resp-4-Plex, with R-squared values of 0.92–0.97, and on average, the Ct values of CoV-2/Flu/RSV <i>plus</i> were higher than that of Resp-4-Plex by 1.86–2.78, except for Flu A1 target (−0.66). To conclude, the performance of both assay was comparable to the SOC methods for both upper and lower respiratory specimens. Implementation of these rapid assay may reinforce the diagnostic capacity for the post-pandemic co-circulation of SARS-CoV-2 and other respiratory viruses.
ISSN:2075-4418