Eurofins Technologies announces the launch of a serology-based total antibody (IgG, IgA and IgM) detection ELISA assay for indirect diagnostic of past exposure to COVID-19. The development of the assay has been led by Eurofins Ingenasa, a Eurofins Technologies company involved in the development of diagnostic tests supporting the control of infectious diseases for over 35 years in veterinary and more recently in human diagnostics.

While molecular diagnostic techniques (PCR) are a direct indicator of the COVID-19 disease, serological tests determine whether a person has been exposed to the infection and has therefore developed antibodies to SARS-CoV-2.

The CE-IVD marked INgezim COVID 19 DR is a dual recognition enzyme-linked immunosorbent assay (ELISA) capable of detecting semi-quantitatively total SARS-CoV-2 virus N-protein-specific antibodies (IgG, IgM and IgA) in a single human serum or plasma sample. The assays use the SARS-CoV-2 nucleoprotein (N protein) as antigen for the detection of antibodies to SARS-CoV-2. The N protein is one of the most abundant early-onset proteins of the virus, as well as being highly immunogenic and therefore a good candidate antigen for the diagnosis of COVID-19.

The assay is capable of detecting any type of antibody specific to the SARS-CoV-2 N protein (IgA, IgG, IgM) without differentiating between them. However, this highly sensitive test is particularly recommended for the early detection of SARS-CoV-2-specific antibodies as it favours the detection of IgM due to its ability to capture more than one conjugated N-protein molecule.

Validation of the assay with a panel of 332 well-characterized sera samples confirmed an analytical sensitivity of 100% from day 17 after symptoms onset (85% between days 7 and 16) and a specificity of 99.2%. No cross-reactivity with other respiratory coronaviruses (229E, NL63, OC43 and HKU1) was detected and no interferences have been found for antibodies for respiratory viruses such as Influenza or RSV.

The ELISA assays determine total antibodies in serum samples with an incubation time of 75 minutes with no requirement for sample pre-dilution. INgezim COVID 19 DR kits are compatible with various open-platform ELISA analyzers.

According to experts, there is a large range of applications for serologic testing. Serology can be used to complement the PCR swab testing that detects the virus to help diagnose acute infections status and its evolution. It can help estimate the timing of infection. As knowledge develops about the immunity to potential reinfection of patients having previously contracted COVID-19 and recovered, antibodies testing may provide information about statistically reduced contagion risks of and from these persons. It could also help identify donors of plasma from recovered patients that can be transfused into COVID-19 patients as a potential treatment.

Eurofins Technologies companies NovaTec, VIROTECH and Gold Standard Diagnostics have previously launched serological tests for the individual determination of IgG, IgM and IgA antibodies in April 2020. Today’s announcement completes the Group’s offering for antibody testing by ELISA.