Clinical performance of two EUA-approved anti-COVID-19 IgG/IgM rapid lateral flow immunoassays using whole blood finger-sticks

Serological, or antibody, tests detect immunoglobulins produced by the hosts plasma B cells following exposure to foreign antigens. Venipuncture blood draws to collect human venous whole blood, plasma from anticoagulated blood (Li+ heparin, K2EDTA and sodium citrate), or serum are commonly utilized and require refrigerated temperatures during transport to the testing facility. Subsequent laboratory testing by enzyme-linked immunosorbent assays (ELISA) or chemiluminescence immunoassays (CLIA) can take an additional 2-5 hours. In the context of the COVID-19 pandemic, rapid diagnostic tests (RDT) to be used in point-of-care (POC) and remote settings have become essential during mandatory quarantine and isolation periods. RDTs allowed for more cost-effective testing using less collection materials with an immediate (5-10 minutes) test result. However, the majority of emerging RDTs receiving Emergency Use Authorization (EUA) approval by the Food and Drug Administration (FDA) for qualitative detection and differentiation of IgM and IgG antibodies to SARS-CoV-2 were only approved for use in human venous whole blood, plasma or serum. In this study we summarize performance characteristics of one RDT (COVID-19 IgG/IgM lateral flow immunoassay rapid cassette) to another by simultaneous application of whole blood finger-stick specimens (n = 32). The study was performed over 5 different days, with daily quality controls consisting of serum previously verified to be positive or negative by COVID-19 IgG/IgM ELISA testing.