New ELISA-Type Immunologic Test Studies Seroprevalence Against SARS-CoV-2

A team of researchers has developed an affordable ELISA-type test that makes it possible to detect IgG and IgM antibodies against the SARS-CoV-2 virus from human serum.

The new ELISA-type immunologic test called DIFELISARS to study the seroprevalence against SARS-CoV-2 has been developed by researchers from the Polytechnic University of Valencia (Valencia, Spain) and is currently in the prototype phase. ELISA-type tests have been applied for decades in various fields of biomedical diagnosis, and they stand out due to their high sensitivity and reliability. Furthermore, they make it possible to analyze a high number of samples simultaneously - up to 120 samples in 180 minutes - which validates its suitability for broad population samplings such as seroprevalence studies.

The DIFELISARS test stands out due to its low cost compared to other existing tests on the market, as well as for its high sensitivity and reliability - classic characteristics of ELISA tests. The test provides a colorimetric signal, proportionate to the concentration of said antibodies, and makes it possible to characterize the sample by comparing positive and negative tests.

The researchers will now validate the test by analyzing a total 200 samples and will also study the differences in the immune response generated - antibody levels - among men and women from the analyzed serum samples. In the study, the team has already started gathering, preparing and characterizing approximately 50 serum samples from patients, which will be used as positive and negative COVID-19 tests. The samples taken will be increased until reaching the 200 needed to conduct the seroprevalence studies.

“The availability of a test of these attributes has now acquired critical importance, as it would allow easy, reliable and cheap monitoring of the individual response of each person during the current vaccination campaign,” said Ángel Montoya, director of the Immunotechnology line of the Ci2B at the Polytechnic University of Valencia.

“Although some ELISAs are currently on sale to detect antibodies against SARS-CoV-2 in human blood products, their price remains high and their real availability is scarce, because large amounts of institutions and governments around the world are trying to acquire them simultaneously in order to conduct their COVID-19 monitoring programs,” added Montoya. “We have worked on this project to tackle this, to get this low-cost test based on existing commercial immunoreactive products ready, which would help facilitate viral seroprevalence studies, while differentiating between sexes, in our immediate surroundings.”

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Polytechnic University of Valencia