Comparative evaluation of the GeneSoC FluA/B Detection Kit for influenza A and B virus detection using archived nasopharyngeal specimens.

BACKGROUND: Rapid nucleic acid amplification tests (rapid NAATs) may facilitate timely influenza diagnosis. This study evaluated the agreement of the GeneSoC® FluA/B Detection Kit (GeneSoC Flu), a rapid NAAT for detecting influenza A and B viruses. METHODS: A preselected panel of 180 nasopharyngeal swab specimens initially classified by prior clinical testing as FluA positive (n = 60), FluB positive (n = 70), or negative (n = 50) was evaluated. The same purified RNA extract from each specimen was tested using GeneSoC Flu, a National Institute of Infectious Diseases (NIID)-based real-time reverse transcription polymerase chain reaction (RT-PCR) method, and the TRexGene SARS-CoV-2&FluA/B Detection Kit. RESULTS: For detection of either influenza A or B virus, the overall percent agreement, positive percent agreement, and negative percent agreement of GeneSoC Flu were 99.4%, 99.2%, and 100.0%, respectively, relative to both the NIID-based method and TRexGene. Only two specimens yielded discordant initial results, and both had very low RNA copy numbers estimated from the NIID-based RT-PCR calibration curve. In addition, the cycle threshold (Ct) values obtained with GeneSoC Flu and TRexGene were strongly inversely correlated with estimated RNA levels (Spearman's ρ, -0.97 to -0.93; p < 0.01). CONCLUSIONS: GeneSoC Flu showed high agreement with the comparator NAATs using shared purified RNA extracts. Prospective evaluation of the complete sample-to-result workflow is required to establish its real-world diagnostic performance and turnaround time.