Review of domestic test systems for detecting current or past SARS‑CoV‑2 infection using enzyme‑linked immunosorbent assay

Abstract

Introduction. Rapid and reliable assessment of circulating antibody levels to SARS-CoV-2 remains the current challenge for monitoring and preventing the spread of COVID-19. As the risk of emergence and dissemination of new viral strains continues to grow, epidemiologic research is also becomes increasingly important. The enzyme-linked immunosorbent assay (ELISA) is useful to assess the vaccination effectiveness and the need for revaccination, the proportion of post-disease and vaccinated individuals, and to monitor population immunity. This article provides an overview of the local ELISA kits currently available for the detection of antibodies against SARS-CoV-2 viral proteins, with a comparison to the certified kit by Mediagnost Ltd. (Germany).The aim. Laboratory testing of seven domestic reagent kits for the determination of antibodies to SARS-CoV-2 viral proteins by ELISA in comparison with the certified test system “Anti-SARS-CoV-2 ELISA E 111-IVD” (Mediagnost Ltd., Reutlingen, Germany).Materials and methods. The study included 80 serum samples from conditionally healthy donors: experimental group (n=70, serum samples collected after 2019) and control group (n=10, serum samples collected before 2018). The experimental group is comprised of non-infected and post-disease individuals; a proportion of those were vaccinated against COVID-19.Results and conclusions. The data obtained indicate high reproducibility, sensitivity (100 %), and specificity for all domestic ELISA kits in detecting both post-disease (90–95 %) and vaccinated volunteers (100 %). The main quality criteria of the obtained results were comparable to those for the certified test system, “Anti-SARS-CoV-2 ELISA E 111-IVD” (Mediagnost Ltd., Germany). All kits detecting IgG to the receptor-binding domain (RBD) and to the S-glycoprotein were effective for the reliable assessment of antibody production after the vaccination. Kits for the detection of antibodies to the RBD and/or viral nucleocapsid are useful for identifying unvaccinated post-disease individuals.