COVID-19 ELISA

High Sensitivity Assays for IgG, IgM, IgA to the N/S-Proteins

An indirect Enzyme-Linked Immunosorbent Assay (ELISA) is a common biochemical technique that is most suitable for determining total antibody concentrations in a sample. This method is commonly utilized to diagnose infection and to quantify antibodies against the invading antigen. In this method, a sample containing the primary antibody is incubated with an antigen-coated plate. Next, a biotin-labeled anti-human detection antibody that recognizes the primary antibody is added. An HRP-conjugated secondary antibody is then added, and when combined with a substrate, produces a signal amplification.

Current testing for the SARS-CoV-2 virus is limited, and compared to RT-qPCR, ELISA is a less complex procedure that uses more affordable and available equipment. Similarly, antigens and antibodies are considerably more stable than RNA, which reduces the potential of false-negative results. The ability to collect samples from many places in the body (and not restricted to nasal swabs) improves testing accuracy as well. Current serology measurements rely entirely on a host’s antibody response to the virus rather than detecting the virus itself. Indirect ELISA has been used to 1) diagnose patients who are more than 1 week post symptom onset, 2) determine potential immunity and risk of infection, 3) advance contact tracing, and 4) understand the extent of COVID19 spread and immunity in communities through epidemiological studies that are particularly important for fighting COVID-19 while minimizing economic impact.