LAUSR

The new epidemic coronavirus SARS-CoV-2 is responsible for severe respiratory illness (i.e. COVID-19). RT-PCR on respiratory samples is the gold standard in COVID-19 diagnosis, while serological tests may contribute to detect post-infection and post-vaccination immunity, and permit seroprevalence studies. The lateral flow immunoassay (LFIA) COVIDTECH® SARS-CoV-2 IgM/IgG Antibody Rapid Test that detects anti-SARS-CoV-2 IgM and IgG using a S-protein recombinant antigen has been independently evaluated in two laboratories. The specificity evaluated on 65 pre-pandemic samples reached 100% for IgM/IgG. Analyzing samples from patients with RT-PCR-confirmed infection, IgM/IgG antibodies were detected in 18/26 (69%) and 58/58 (100%) samples before day 13th and from the 14th day post-symptom onset respectively. Before the 14th post-symptom onset, the COVIDTECH test was less sensitive than another LFIA method (BioSynex BSS IgM/IgG) and a chemiluminescent Immunoassay (LIAISON® SARS-CoV-2 TrimericS IgG assay). Overall, this LFIA method is suitable for SARS-CoV-2 serological diagnosis, when the patient is > 14th day after onset of symptoms.