Key features of tests for detection of SARS-CoV2 antibodies

Abstract

On March 11, 2020, the World Health Organization recognized the outbreak of the disease COVID-19 (Coronavirus Disease 2019) and the spread of the new coronavirus (SARS-CoV-2), which caused this disease, as a pandemic. The SARS-CoV-2 virus stimulates the production of antigen-specific antibodies for which commercial tests have been developed. The issue of diagnosing antibodies to SARS-CoV-2 became especially acute together with the beginning of mass vaccination of the population. Due to the fact that the reading of the result depends on the test format, it is necessary to understand how the antigenic target, the composition of the immunoglobulins and the way of expressing the result affect its interpretation. When analyzing the literature, it was found that with COVID-19, antibodies to the nucleocapsid antigen of SARS-CoV-2 can be detected somewhat earlier than antibodies to the spike antigen; virus-neutralizing antibodies are directed to the receptor-binding domain, seroconversion of immunoglobulins M and G begins simultaneously, and tests for total antibodies are potentially more sensitive due to the ability to capture antibodies with various features of the immune response. The problem of incomparability of quantitative results obtained on different systems is also noted. These factors must be taken into account when choosing a test for detecting antibodies to SARS-CoV-2, which will adequately solve a specific clinical and epidemiological problem.