Abstract
Rapid identification of respiratory pathogens, such as influenza virus A (FluA), influenza virus B (FluB), and respiratory syncytial virus (RSV), reduces unnecessary antimicrobial use and enhances infection control practice. We performed a comparative evaluation of three molecular methods: (i) the Aries Flu A/B & RSV, (ii) the Xpert Xpress Flu/RSV, and (iii) the Cobas Flu A/B & RSV assays. The clinical performances of the three methods were evaluated using 200 remnant nasopharyngeal swab (NPS) specimens against a combined reference standard. The limits of detection (LODs) were determined using FluA, FluB, and RSV control strains with known titers. The 95% LODs were between 1.702 and 0.0003 50% tissue culture infective dose (TCID(50)), with no significant differences revealed among the three assays. Perfect qualitative detection agreement was obtained in the reproducibility study. The Cobas assay failed at the first run on 13 clinical specimens, resulting in an invalid rate of 6.5%. The sensitivities and specificities for all assays were 96.0 to 100.0% and 99.3 to 100% for all three viruses. For on-demand single-specimen and batched 12-specimen workflows, the test turnaround times were 115.5 and 128.8 min for the Aries assay (12 sample capacity), 34.2 and 44.2 min for the Xpress assay (16 sample capacity), and 21.0 and 254.4 min for the Cobas assay (one instrument), respectively. In summary, the Aries, Xpress, and Cobas Liat assays demonstrated excellent sensitivities and specificities for simultaneous detection and identification of FluA, FluB, and RSV from NPS specimens in cancer patients. Test turnaround time was significantly shorter on the Xpress when instrument scalability is unlimited.