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Elina Labs is the exclusive provider of the GenScript cPass SARS-CoV-2 Neutralization Antibody Detection Test (cPass) in Georgia.
Various types of tests (assays) are used to determine different aspects of immune response and the functionality of antibodies. These tests can be broadly classified to detect either Neutralizing Antibodies or Binding Antibodies.
Neutralizing Antibody Detection
Neutralizing antibodies are an important specific defense against viral invaders. Neutralizing antibodies not only bind to a virus, but they also bind in a manner that blocks infection.
A neutralizing antibody might block interactions with the receptor or might bind to a viral capsid in a manner that inhibits uncoating of the genome. Only a small subset of the many antibodies that bind a virus is capable of neutralization. After infection, it can take some time for the host to produce highly effective neutralizing antibodies but these persist to protect against future encounters with the agent.
At this time, scientists do not know how long antibodies to SARS-CoV-2 can be detected. An article published by WebMD in April 2021 stated that both Pfizer and Moderna may recommend another vaccine in 12 months and annually thereafter.
In a recent article published by Johns Hopkins University, authors state "neutralization assays are the gold standard for determining if a patient has effective antibodies and protective immunity against SARS-CoV-2. The ability of antibodies to prevent viral replication and clear infection is determined through neutralization assays."
The cPass test was granted Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA) on November 6, 2020.
The cPass test is the first blood test that detects the Neutralizing Antibodies that the COVID-19 vaccine is designed to produce. The cPass test is a “surrogate Viral Neutralization Test (sVNT)”. These significant technical innovations which allow for samples to be processed in less time than the traditional viral neutralization tests which can take 3-5 days to produce results. Because these tests do not require live virus, they can be conducted in clinical laboratories.
The test will measure and quantify the neutralizing capacity of antibodies against the SARS-CoV-2 virus. Unlike other types of tests currently on the market, the cPass test detects the presence and magnitude of neutralizing antibodies that prevent infectivity of the COVID-19 virus.
Binding Antibody Detection
Not all antibodies that bind to a pathogenic (disease-causing) particle are neutralizing. Non-neutralizing antibodies, or Binding antibodies, bind specifically to the pathogen, but do not interfere with their infectivity.
There are binding antibody tests that are accessible, but these do not provide accurate results on the neutralizing characteristic of the antibodies the human body produces against SARS-CoV-2. The following types of binding antibody tests available are:
- IgM is most useful for determining recent infection as it usually becomes undetectable weeks to months following infection.
- IgG may remain detectable for months or years.
- IgA is important for mucosal immunity and can be detected in mucous secretions like saliva in addition to blood. Its significance related to COVID-19 is still to be determined.
These types of binding antibody tests are typically a rapid, in-office test performed in 15 minutes by a medical provider.