Comparing the Cobas Liat Influenza A/B and respiratory syncytial virus assay with multiplex nucleic acid testing

Gosert, Rainer; Naegele, Klaudia; Hirsch, Hans H.

Influenza virus and respiratory syncytial virus (RSV) detection with short turn‐around‐time (TAT) is pivotal for rapid decisions regarding treatment and infection control. However, negative rapid testing results may come from poor assay sensitivity or from influenza‐like illnesses caused by other community‐acquired respiratory viruses (CARVs). We prospectively compared the performance of Cobas Liat Influenza A/B and RSV assay (LIAT) with our routine multiplexNAT‐1 (xTAG Respiratory Pathogen Panel; Luminex) and multiplexNAT‐2 (ePlex‐RPP; GenMark Diagnostics) using 194 consecutive nasopharyngeal swabs from patients with influenza‐like illness during winter 2017/2018. Discordant results were reanalyzed by specific in‐house quantitative nucleic acid amplification testing (NAT). LIAT was positive for influenza virus‐A, ‐B, and RSV in 18 (9.3%), 13 (6.7%), and 55 (28.4%) samples, and negative in 108 samples. Other CARVs were detected by multiplexNAT in 66 (34.0%) samples. Concordant results for influenza and RSV were seen in 190 (97.9%), discordant results in 4 (2.1%), which showed low‐level RSV (<40 000 copies/mL). Sensitivity and specificity of LIAT for influenza‐A, ‐B, and RSV were 100%, 100% and 100%, and 100%, 99.5% and 100%, respectively. The average TAT of LIAT was 20 minutes compared to 6 hours and 2 hours for the multiplexNAT‐1 and ‐2, respectively. Thus, LIAT demonstrated excellent sensitivity and specificity for influenza and RSV, which together with the simple sample processing and short TAT renders this assay suitable for near‐patient testing.