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A team of researchers at  and the University of Toronto is in the early stages of developing a blood test that can identify who is immune to COVID-19 on a mass scale.

The test is an adaptation of an ELISA assay (enzyme-linked immunosorbent assay) and has the potential to enable hospitals and other institutions to screen up to 10,000 samples at once, allowing entire workforces to be tested efficiently.

The blood-based test, which the team hopes to test on volunteers within the next two weeks, does not directly detect the live virus and is not intended to replace current tests for infection. 

Anne-Claude Gingras, project co-lead, said the test works by detecting antibodies in the immune system of infected patients. Those antibodies persist in blood even after the virus has been completely eliminated.

“The entire city has come together to make this possible,” said Gingras, a senior investigator at Sinai Health’s (LTRI) and a professor of molecular genetics at U of T. “This test is being developed with the goal of monitoring the percentage of the population that has been infected and to help in identifying those individuals that may have protective immunity.”

The project is a collaboration between Gingras and Jeff Wrana, also a senior investigator at LTRI and a professor of molecular genetics at U of T, and other researchers from the Faculty of Medicine.

The team includes James Rini, a professor of biochemistry and molecular genetics who was key to producing proteins for the assay, and Professors Jennifer Gommerman and Mario Ostrowski from the department of immunology, who helped supply samples from pre-pandemic subjects as well as patients infected early in the pandemic who have since recovered.

The new ELISA test can provide valuable information about the spread of SARS-CoV-2 in Canada, said Karen Maxwell, an assistant professor of biochemistry who is helping to co-ordinate COVID-19 research at U of T.

“This test will allow us to track the true spread and magnitude of the disease,” Maxwell said. “Determining who has been infected and has antibodies will be important information for making decisions about how and when we return to our normal activities.”

The test will make use of the robotics platform at LTRI. Jim Woodgett, director of research at LTRI and a professor of medical biophysics at U of T, said such advances are possible thanks to close collaboration between scientists across institutions.

“Sinai Health and the University of Toronto are ideally positioned to develop this critically important antibody-based test,” Woodgett said. “This research group is eager to contribute in any way possible to help Canada overcome this historic public health challenge.”