Efficacy of POC Antibody Assays after COVID-19 Infection and Potential Utility for "Immunity Passports"

Abstract

Objective: Numerous manufacturers market lateral flow assays for the detection of SARS-CoV-2 antibodies, but there are many questions about the reliability and efficacy of these tests.

Materials and methods: Serum specimens from 60 individuals were analyzed using 2 lateral flow antibody assays, an in-house enzyme-linked immunosorbent assay (ELISA), and the Abbott SARS-CoV-2 IgG chemiluminescent immunoassay.

Results: The BioMedomics and Premier Biotech lateral flow assays were positive for IgM in 73.3% and 70% and for IgG in 80% and 73.3% of specimens, respectively. The ELISA assay was positive for IgM and IgG in 73.3% and 86.7% of specimens from infected individuals, whereas the Abbott assay was positive in 80%. The specificities of the 4 assays ranged from 96.7% to 100% for IgM and from 93.3% to 100% for IgG.

Conclusion: Results of the 2 lateral flow assays were comparable to those of the ELISA and Abbott assays. Assay efficacy depended on length of time after SARS-CoV-2 infection.

Keywords: COVID-19; ELISA; SARS-CoV-2; antibody tests; lateral flow assays.