COVID-19: An Improved ELISA Test for Rapid Antibody Detection Provides Edge Over Current Players

By Ruchi Jhonsa, Ph.D.

The ongoing coronavirus pandemic has taken many lives and disrupted the economy to a great extent in the past few months. However, the situation is under control, thanks to companies and institutions that quickly rolled out RT-PCR tests for the detection of coronavirus. While such tests played an essential role in diagnosis and monitoring of genetic changes of the virus, an urgent need exists for a reliable serological test that can determine retrospective contact tracing, investigate infection rate in asymptomatic patients, assess herd immunity and protective immunity in recovered patients, and define “lockdown exit strategy.”

Currently, there are 42 USFDA emergency authorized serological tests that can detect total binding and neutralizing antibodies against the virus in a patient’s blood. They are either based on conventional tests that use live viruses or pseudoviruses for the detection of antibodies or ELISA based tests that use antigens derived from the virus. While ELISA based assays are safer and simpler to perform than the conventional tests, they detect total binding antibodies and fail to distinguish between total binding and neutralizing antibodies.

An improvement over the existing ELISA tests is the newly launched ADMA biologics ImmunoRank Neutralization MICRO-ELISA test, a proprietary, fully-validated that specifically detects neutralizing antibodies in the plasma. The test is jointly developed with Leinco Technologies, Inc. and is intended to identify individuals who developed neutralizing antibodies against the virus following recent or prior infection. An important property of the test, however, is its ability to detect all types of immunoglobulins in the plasma, including IgM. This is important, according to the CDC, that believes that “IgM is most useful for determining recent infection as it usually becomes undetectable weeks to months following infection, while IgG may remain detectable for months or years.”

Besides being able to detect multiple immunoglobulin types, the test can also run up to 90 samples at once with 99.8% specificity. “Current screening methods to identify circulating SARS-CoV-2 neutralizing antibodies are labor and cost-intensive and take multiple days to complete,” said Adam Grossman, President and Chief Executive Officer of ADMA. “This assay can be run in approximately 80 minutes, resulting in numerous tests per day, and can be performed at a fraction of the cost of other, more laborious assays.”

The test is currently not approved by the USFDA. However, ADMA is preparing the paperwork for the FDA emergency approval that is imminent. Meanwhile, it is getting patent protection in the U.S and certain foreign countries for technology.

The duo of inventors has decided to specific terms and conditions that will guarantee market access to both the parties following product approval. Specifically, ADMA will have the right to use, market, and commercialize ImmunoRank for the selection and screening of human plasma containing SARS-CoV-2 antibodies, for manufacturing products such as plasma proteins for therapeutic use, for the screening of convalescent plasma donors or vaccinated plasma donors, as well as combining these products with SARS-CoV-2 neutralizing monoclonal antibodies. ADMA will also have the right to sell ImmunoRank test kits to plasma donation centers to screen donors for neutralizing antibodies. Leinco, on the other hand, will manufacture the kits and sell to markets other than the ones reserved for ADMA.

The WHO has recently cautioned that a positive result on a serological test does not necessarily mean protective immunity. This is because most of the currently available tests detect binding antibodies and does not measure true neutralizing antibodies. ADMA’s validated test, which can detect neutralizing antibodies quickly in an ELISA based format, is, therefore, better over other tests and can give an accurate measure of the protective immunity raised against the virus.

Editor: Rajaneesh K. Gopinath, Ph.D.

Related Article: COVID-19: USFDA Approves Abbott’s $5 Test, BinaxNOW™ for Rapid Diagnosis

References

1. https://www.admabiologics.com/investors/press-releases/detail/477/adma-biologics-highlights-launch-of-covid-19-immunorank
2. https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antibody-tests-guidelines.html#:~:text=Although%20scientists%20do%20not%20know,detectable%20for%20months%20or%20years
3. https://www.nature.com/articles/s41587-020-0631-z
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7263515/

Author

Ruchi Jhonsa