Three types of assays are used to monitor COVID-19 infection: detection of the virus by a molecular test (PCR), by an antigen test, and serological assays that detect antibodies produced upon infection.

Serological assays allow for the assessment of immunological status of individuals. They may also serve as an adjunctive tool to complement PCR, associated in some cases with false negatives, for helping to assess virus exposure. They help to determine the virus prevalence in general populations and to characterize the immune response in high-risk communities. The assays are essential to guide pandemic management by identifying those who have developed an adaptive immune response and thus, those who have been exposed to the virus.

Antibodies detected during infection are IgM, IgG and IgA. Bio-Rad’s Platelia SARS-CoV-2 Total Ab is a serological assay that detects the three types of antibodies, allowing early or later diagnosis of infection by identifying people with an immune response to the virus. Fast product development, as required by the unprecedented pandemic may lead to underperforming assays. However, Bio-Rad leveraged studies performed during the 2003 SARS outbreak and the SARS-CoV-2 assay was further optimized to address these new diagnostic challenges. It offers more than 99% specificity (99.6% from blood donor specimens) and its sensitivity is excellent as concluded from longitudinal clinical studies of patients infected with SARS-CoV-2, yielding an overall 98% sensitivity and 100% for patients tested greater than eight days after symptom onset. It exhibits a complete absence of cross-reactivity with common coronaviruses and other respiratory viruses.

Based on performance, the Platelia SARS-CoV-2 Total Ab assay was granted FDA EUA and CE marking, and was notably validated by the French National Reference Center for reimbursement in France. The assay can be processed on open automated microplate platforms, such as the validated Bio-Rad EVOLIS system. Running on Bio-Rad instruments offers security and full traceability of results. The assay can also be performed manually or on other automated platforms, bringing flexibility of use by making it accessible to all types of users, hospitals, or analytical laboratories. This assay is adapted to different testing volumes ranging from a few samples to several hundred per day.

For more information, visit: https://www.bio-rad.com/diagnostics