Two serological approaches for detection of antibodies to SARS-CoV-2 in different scenarios: A screening tool and a point-of-care test

Hoste, Alexis C.R.; Venteo, Angel; Fresco-Taboada, Alba; Tapia, Istar; Monedero, Alejandro; López, Lissette; Jebbink, Maarten F.; Pérez-Ramírez, Elisa; Jimenez-Clavero, Miguel Angel; Almonacid, Mercedes; Muñoz, Patricia; Guinea, Jesus; Vela, Carmen; van der Hoek, Lia; Rueda, Paloma; Sastre, Patricia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected more than 8 million people worldwide, becoming a pandemic. Detecting antibodies against SARS-CoV-2 is of utmost importance and a good indicator of exposure and circulation of the virus within the general population. Two serological tools based on a Double Recognition assay (Enzyme-Linked Immunosorbent Assay, DR-ELISA and Lateral Flow Assay, DR-LFA) to detect total antibodies to SARS-CoV-2, have been developed based on the recombinant nucleocapsid protein. A total of 1065 serum samples, including positive for COVID-19 and negative samples from healthy donors or infected with other respiratory pathogens, were analyzed. The results showed values of sensitivity between 91.2%–100%, and specificity of 100%–98.2%, for DR-LFA and DR-ELISA, respectively. No cross-reactivity against seasonal coronavirus (HCoV-NL63, HCoV-229E, HCoV-HKU1, HCoV-OC43) was found. These results demonstrate the importance of serology as a complementary tool to PCR, for follow up of recovered patients and identification of asymptomatic individuals.