Background Cycle threshold (Ct) values from SARS-CoV-2 nucleic acid amplification tests have been used to estimate viral load for treatment decisions. Additionally, there is a need for high-throughput testing, consolidating a variety of assays on one random-access analyzer. Objectives In this study, the clinical performance of the Alinity m SARS-CoV-2, RealTi m e SARS-CoV-2, and GeneXpert Xpress SARS-CoV-2/Flu/RSV assays was assessed. Methods Alinity precision and detection rates were evaluated using a dilution series of the Alinity m SARS-CoV-2 positive control. In a retrospective study, 7 remnant external quality assessment (EQA) specimens and 200 remnant nasopharyngeal swab specimens (100 positive and 100 negative) were tested in the three assays. Results Alinity had 100 % detection rate at 50 copies/mL and high reproducibility (Ct value coefficient of variation ≤3.1 %). All three assays correctly detected positive and negative EQA samples with comparable Ct values (max difference 2.38) and high linearity. In patient samples, positive percent agreement was 95 % (95 % CI 89–98 %) and negative percent agreement was 100 % (95 % CI 96–100 %) for Alinity, compared to the other two assays. Four specimens detected on Alinity m but not RealTi m e or Xpert had Ct values above 40. Assay results were highly correlated (r ≥ 0.94). Ct values (after addition of 10 unread cycles to the reported Ct of RealTi m e) were comparable across the three assays. Conclusions Alinity m had high precision and accuracy and Ct values comparable to those of the RealTi m e and Xpert assays. The assays could be used interchangeably, with no need for adjustment of patient management decisions based on Ct values from each assay. Highlights • 100 % detection rate at 50 copies/mL with Alinity m SARS-CoV-2. • Alinity m SARS-CoV-2 showed high reproducibility with CV% of Ct values ≤ 3.1 %. • Percent agreement between Alinity m, RealTime and Xpert assays was 95–100 %. • Results suggest slightly higher sensitivity of Alinity m versus RealTi m e and Xpert. • Low mean Ct differences of 1.10–2.55 between Alinity m, RealTime, and Xpert.
【저자키워드】 SARS-CoV-2, respiratory viruses, Real-time PCR, Alinity m,