Multicenter clinical performance and comparative evaluation of the LIAISON PLEX Respiratory Flex Assay for syndromic detection of viral and bacterial pathogens in nasopharyngeal swabs.

UNLABELLED: The LIAISON PLEX Respiratory Flex Assay is a customizable syndromic molecular assay for the qualitative detection of nucleic acids from 14 viral and 5 bacterial respiratory pathogens in nasopharyngeal swabs (NPS). This study evaluated its clinical performance in comparison to established FDA-cleared and standard-of-care molecular diagnostic platforms. A total of 2,099 NPS specimens were prospectively and retrospectively collected. Positive Percent Agreement (PPA), Negative Percent Agreement (NPA), and diagnostic accuracy were calculated across 19 targets. The assay was benchmarked against SOC assays, including Cepheid Xpert Xpress CoV-2/Flu/RSV Plus, Abbott Alinity m Resp-4-Plex, and BioFire RP 2.1 panel. Agreement metrics, kappa coefficients, and discordance analysis were used to assess the comparative performance. For bacterial targets, PPA ranged from 92.3% to 100%, with NPA exceeding 99%, and diagnostic accuracy above 99.7%. Viral targets showed PPA from 90.3% to 100% and NPA from 95.8% to 100%. Adenovirus, Influenza A, and Influenza B achieved 100% PPA. RSV and SARS-CoV-2 demonstrated diagnostic accuracies of 99.7% and 99.0%, respectively. Agreement with SOC assays was high (PPA up to 97.1%; kappa 0.81-0.97). Discordance analyses identified differences in pathogen detection, with the Respiratory Flex Assay detecting analytes missed by SOC assays. The LIAISON PLEX Respiratory Flex Assay demonstrated high accuracy, reliability, and strong diagnostic agreement with SOC assays. Its robust performance across respiratory pathogens supports its use as a comprehensive diagnostic tool for respiratory infection management.

IMPORTANCE: Fast and accurate detection of respiratory pathogens helps guide treatment, lower healthcare costs, and support disease monitoring. The LIAISON PLEX Respiratory Flex Assay was evaluated for respiratory pathogen detection by comparing its performance to FDA-cleared molecular respiratory pathogen detection methods, PCR followed by bi-directional sequencing (PCR/BDS) for bacterial pathogens, and standard-of-care (SOC) molecular respiratory assays, including targeted and multiplex syndromic PCR panels. The study assessed its ability to identify pathogens associated with respiratory tract infections, measure agreement with SOC assays, and determine its accuracy in clinical settings. The findings provide data on the assay's diagnostic performance, testing flexibility, and applicability in laboratory workflows.