Performance of Three SARS-CoV-2 Immunoassays, Three Rapid Lateral Flow Tests, and a Novel Bead-Based Affinity Surrogate Test for the Detection of SARS-CoV-2 Antibodies in Human Serum

For the control of immunity in COVID-19 survivors and vaccinated subjects, there is an urgent need for reliable and rapid serological assays. Based on samples from 63 COVID-19 survivors up to 7 months after symptom onset, and on 50 serum samples taken before the beginning of the pandemic, we compared the performances of three commercial immunoassays for the detection of SARS-CoV-2 IgA and IgG antibodies (Euroimmun SARS-COV-2 IgA/IgG, Mikrogen recomWell SARS-CoV-2 IgA/IgG, and Serion ELISA agile SARS-CoV-2 IgA/IgG) and three rapid lateral flow (immunochromatographic) tests (Abbott PanBio COVID-19 IgG/IgM, Nadal COVID-19 IgG/IgM, and Cleartest Corona 2019-nCOV IgG/IgM) with a 50% plaque-reduction neutralization test (PRNT50) representing the gold standard. Fifty-seven out of 63 PCR-confirmed COVID-19 patients (90%) showed neutralizing antibodies. The sensitivity of the seven assays ranged from 7.0% to 98.3%, and the specificity ranged from 86.0% to 100.0%. Only one commercial immunoassay showed a sensitivity and specificity of greater than 98%.