Performance of Two Molecular Point-of-Care Influenza A/B Tests Compared to the Cepheid Xpert Xpress Flu/RSV Assay

Molecular point-of-care testing (POCT) platforms have demonstrated considerable utility in rapid and accurate influenza diagnostics. Among them, the Cepheid Xpert is widely used in clinical practice, while Coyote Flash10 and Genewise NAT-3000 were recently approved, with few performance data available. Performances of Flash10 and NAT-3000 were evaluated in parallel with the Xpert assay. The limits of detection (LoDs) were determined using serially diluted standard reference materials of inactivated influenza virus A and B (FluA/B). Clinical performance was assessed using 200 remnant nasopharyngeal swab specimens. Other assay features were also compared. All three platforms featured comparable hands-on procedures and turnaround times ranging from 26 to 33 min. The Xpert assay was more sensitive than the other two, with the lowest LoDs at 72.6, 49.3, 213.2, and 66.8 copies/mL for FluA H1N1, FluA H3N2, FluB Victoria, and FluB Yamagata, respectively. The Flash10 and NAT-3000 assays showed similar LoDs for FluA, ranging from 483.4 to 576.8 copies/mL; for Victoria and Yamagata, their LoDs were 296.4 and 92.7 copies/mL for Flash10 and 1419.1 and 591.0 copies/mL for NAT-3000. Clinical performance revealed high concordance across assays. Positive and negative percentage agreements ranged from 93.33% to 100.00%, along with high Kappa values ranging from 0.94 to 0.95. Linear regression analysis showed moderate to strong associations between the cycle threshold values of positive specimens. The two new molecular POCT platforms were similarly user-friendly and showed comparable performance to the Xpert platform for FluA/B detection, despite their higher LoDs, indicating they are potential alternatives for rapid respiratory virus detection.