With the COVID-19 pandemic growing globally, new ways of detecting the infection is the need of the hour. The test, called the SARS-CoV2 DETECTR assay, checks for the presence of two specific regions in the novel corona virus – one is found in all ‘SARS-like’ corona viruses and one is unique to SARS-CoV-2, which causes COVID-19. This helps to differentiate COVID-19 infections from similar infections caused by other corona viruses.
The assay is currently being validated in a Clinical Laboratory Improvement Amendments (CLIA)-certified microbiology laboratory as per guidelines from the FDA.
As one of the first tests to use CRISPR gene-targeting to detect the novel corona virus, this technology offers several benefits over current qRT-PCR testing. PCR (polymerase chain reaction) is a specialized, expensive technique that can only be performed in well-equipped labs. The DETECTR assay, on the other hand, can be performed in any lab with off-the-shelf reagents and common equipment, making it a more cost-effective and widely available solution.
Another key advantage of the DETECTR assay is the <60 minute readout time, while PCR-based tests take up to four hours. The test sensitivity is slightly lower (10 virus particles/microliter of fluid) compared to PCR-based tests (3.5 virus particles/microliter); however, this is unlikely to be a huge disadvantage due to the high viral load in most COVID-19 positive patients.
One major disadvantage of both techniques is the RNA extraction step, which has proved to be time-consuming due to the lack of availability of reagents and equipment. Manual extraction of 1-8 samples still takes 10 minutes, and automated extraction is a limited option due to the specialized equipment and reagents required.
Ultimately, a test that directly measures the viral antigen (as is the case in the test for influenza), instead of requiring RNA extraction, will eliminate these drawbacks. Until then, the rapid development of such novel techniques will help improve testing rates to combat the pandemic.
To diagnose COVID-19 so that correct isolation or treatment efforts can be executed, or detecting antibodies, leading to the identification of those with immunity and the ability to go back to work. It is a great responsibility of those in diagnostics to inform those making key decisions.
However, with limited diagnostic testing happening in many countries, many people who were infected and symptomatic never received a formal diagnosis, and many people have been infected but didn’t display any symptoms and so never knew they were infected in the first place. One answer to this dilemma is an antibody test that can be used to detect the presence of antibodies to COVID-19 in patient samples, to confirm that they have been infected, and so may have immunity.
The “immunity passport,” is a permit that confirms that someone has already been infected by the virus and has recovered, and so they could potentially be allowed to return to work.
To be able to show that we have immunity to issue an immunity passport, we need reliable antibody testing, which tells if our body has the antibodies specific to SARS-CoV-2 because we fought off the coronavirus.
It takes about a week or longer for antibodies against the virus to appear in the blood if a person has been infected according to Louis Mansky, the director of the Institute for Molecular Virology at the University of Minnesota Twin Cities.
In a recent development, The U.S. Food and Drug Administration granted its first-ever emergency use authorization for the gene-editing technology CRISPR on Thursday, green lighting a corona virus diagnostic test developed by Cambridge, Massachusetts-based Sherlock Biosciences.