AUTHOR=Fernández-Rivas Gema , Barallat Jaume , Gonzalez Victoria , Martinez Silvia , Bordoy Antoni E. , Jimenez Laura , Casañ Cristina , Blanco Ignacio 

TITLE=Analytical Performance of Quantitative DiaSorin Liaison SARS-COV-2 Antigen Test for the Asymptomatic Population

JOURNAL=Frontiers in Public Health

VOLUME=Volume 9 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.788581

DOI=10.3389/fpubh.2021.788581

ISSN=2296-2565

ABSTRACT=SARS-CoV-2 antigen tests have been widely employed to identify patients for a rapid diagnosis and pandemic control. Rapid lateral-flow techniques are currently the most used, but automated technologies have emerged as another viable alternative to molecular methods.  We aimed to evaluate the analytical performance of DiaSorin Liaison SARS-CoV-2  Antigen Test in asymptomatic population and close contacts, for its use as a tool in pandemic control efforts. A retrospective study was conducted and a total of 861 samples were included, 291 (34%) were positive for SARS-CoV-2 with Ct<40 and 570 (66%) were negative. A strong correlation was observed between RT-PCR Ct and Antigen TCID50/mL (r=0.6486; p<0.0001) and all RT-PCR negative samples tested negative for the 200 TCID50/mL SARS-Cov-2 antigen cutoff, i.e. a specificity of 100% was reached (95% CI: 99.4-100.0%). Samples with <25 Ct and/or >106 extrapolated copies/mL reached a sensitivity of 100% (95% IC 97.0 – 100.0%). For intermediate viral loads (>105 extrapolated copies/mL or <30 Ct) the sensitivity value still exceeded 80%). As with other antigen methods, samples between 30-40 Ct could not be detected with a reliable sensitivity.  The LIAISON® SARS-CoV-2 Ag assay displays an acceptable sensitivity and a very high specificity that is useful for detecting the presence of SARS-CoV-2 in nasal swabs of asymptomatic population or to regular monitoring of risk groups in controlled settings. Additionally, the flexibility in processing different samples and in the sampling preparation process makes this test an option for its use in high throughput laboratories. Automated tests may facilitate result reporting and yield consistent data, while avoiding some of the pitfalls of rapid lateral-flow techniques, such as observer variability.