GenScript USA, a research reagent provider, said that the U.S. FDA has granted Emergency Use Authorization (EUA) for the cPass SARS-CoV-2 Neutralization Antibody Detection Kit. This is the first commercially available test to specifically detect neutralizing antibodies without the use of live virus. Neutralizing antibodies, a subset of antibodies that are specifically able to block the ability of the virus to enter a cell, are widely recognized biomarkers of immunity. The test measures the presence of neutralizing antibodies in any sample, from those from patients recovering from COVID-19 or those vaccinated against SARS-CoV-2. 
 
The conventional method for measuring neutralizing antibodies requires testing to be performed in a high safety-level facility (BSL3) staffed with specialized personnel. Typically, results from the live virus assay are available in several days and due to the unpredictable nature of the live virus and live cells reagents used, these tests are also difficult to standardize. Results from different facilities may vary, even if performed using the same protocol. In contrast, the cPass kit utilizes pure proteins that can be produced in a more reproducible way.
 
The detection of the presence of neutralizing antibodies can also be performed in most standard research or clinical diagnostic laboratories with short turnaround time (~1hr), making it broadly available and much more consistent between different facilities. Furthermore, a comparison of the direct clinical performance between the conventional live virus and the cPass assay shows results from both tests are strongly correlated.
 
“Unlike commercially available antibody-based tests that are routinely used for detecting prior exposure to the virus, the cPass kit can assess both prior exposure and the presence of neutralizing antibodies in convalescent patients,” said David Martz, vice president of new product management in Life Science Group at GenScript. “The cPass kit is also a valuable tool for assessing vaccine performance. When vaccine companies start phase II or III trials, a standardized test that can detect neutralizing antibodies will be needed for a large cohort of patients to evaluate the efficacy of vaccines within different populations and regions.”
 
“The cPass test can also be used to screen animals for SARS-CoV-2 infection without modification, as it works in a species-independent manner,” added Professor Linfa Wang from the Programme in Emerging Infectious Diseases of Duke-National University of Singapore Medical School, whose team pioneered the development of this novel test platform.