FDA Authorizes IgG Antibody Test for SARS-CoV-2

The US Food and Drug Administration (FDA) has granted Emergency Use Authorization (EUA) to a laboratory-based immunoglobulin G (IgG) antibody test for the detection of SARS-CoV-2 virus in users.

The EUA, granted to Quansys Biosciences for its proprietary Q-Plex SARS-CoV-2 Human IgG (4-Plex) Assay, instantly introduces an assay to the market that can simultaneously detect human IgG antibodies that recognize S1 and S2 subunits of the virus’ spike protein from the same sample.

Positive IgG antibody results from the test can identify patients who have been exposed to SARS-CoV-2 and have demonstrated an immune response. The test’s ability to detect the S1 subunit, which contains the receptor binding domain of the spike protein, was adequate for the requirements of the EUA alone, according to Quansys.

But the addition of assessing S2 subunit measurements to the clinical increased the test’s accuracy to 97.4% sensitivity and 99.7% specificity.

In a statement accompanying the authorization, Quansys Biosciences Chief Executive Officer Adam Brown stressed the importance of high-specificity SARS-CoV-2 testing devices—especially in long-term management strategies.

"High quality tests are essential as we work to better control the SARS-CoV-2 pandemic,” he explained. “In addition, improved quality and accuracy of the assay is vital to correctly evaluate the spread of this virus, which varies across communities.”