Author: Flora Wong
In roughly three months, the never-before-seen coronavirus swept across the globe, infecting at least a million people from 199 different countries and territories. Although more and more countries seem to be fighting a losing battle with SARS-CoV-2, South Korea, Singapore and Hong Kong have turned heads for their ability to contain the spread of this virus, despite being so close to China. By implementing widescale testing much earlier than other countries, infected individuals, as well as those who may have come into contact with them, were quickly identified and put under strict quarantine, preventing the uncontrollable spread of this virus in these countries.
A roadside SARS-CoV-2 swab test conducted in Israel on March 31, 2020. (Source: JACK GUEZ/AFP VIA GETTY IMAGES)
So, it’s clear that widescale testing is one step that needs to be taken in order to track and slow down the spread of SARS-CoV-2 in the rest of the world. But what’s preventing this from happening? To answer this question, it may help to understand how SARS-CoV-2 diagnostic tests actually work. Currently, a nasopharyngeal swab is collected from a patient and sent to a certified lab where RNA is first extracted from the sample. Reverse transcription polymerase chain reaction (RT-PCR) is then performed using the extracted RNA to detect the presence of SARS-CoV-2 genes in the sample.
Although this process is the gold standard for diagnosing patients who may be infected with a virus, several bottlenecks are appearing as widescale testing is slowly being introduced around the world. The test itself generally takes 4-6 hours to complete, however, since trained staff and lab equipment are needed to process the clinical samples, they need to be shipped to laboratories, which increases the time it takes to get a test result by about 1-2 days. Take into consideration the thousands of swabs that are getting sent to the few laboratories that are approved to run these SARS-CoV-2 diagnostic tests, and now we have a wait time of up to 1 week. As of March 28, 184,000 people were tested in Canada, but more than 8,600 people in Ontario alone were still waiting for results.
Fortunately, biotech companies are scurrying to develop rapid point-of-care SARS-CoV-2 tests that can deliver results in minutes, without the need to send samples out to centralized laboratories for processing. SBL Testing Technologies, based in Calgary, Canada, has developed a FDA-approved rapid testing device that can deliver results in just 15 minutes. These tests require a drop of blood from the patient’s finger, which will be used to determine if the patient has antibodies against SARS-CoV-2. However, antibody-based diagnostic tests are not as accurate as those that use PCR or RT-PCR since antibodies take about two weeks to be produced in response to an infection. This means that people who were recently infected with SARS-CoV-2 could receive negative test results from this testing kit.
However, on March 27, an even faster, more accurate rapid point-of-care test was granted approval by the FDA under its Emergency Use Authorization. Developed by Abbott Laboratories, the test follows the gold standard method for detecting SARS-CoV-2 via RT-PCR, with positive results delivered in as little as 5 minutes and negative results in 13 minutes.
Abbott ID NOW system (source: Abbott)
The test runs on Abbott’s ID NOW Instrument, which is a small fluorescence-based benchtop instrument that is already widely available in doctors’ offices and emergency rooms in the U.S. and is currently being used to detect Influenza A&B, Strep A and respiratory syncytial virus. The Instrument houses test cartridges that contains all of the reagents needed for RNA extraction and for the amplification of genes that are unique to the virus being tested for. All that is needed is a nasopharyngeal swab from the patient, which is swirled in one of the cartridges for about 10 seconds. Once that happens, the ID NOW Instrument qualitatively detects if the infectious disease is present in the patient sample by isothermally amplifying the bacterial or viral nucleic acids, while incorporating fluorescent probes onto the amplicons. If the fluorescent signal surpasses a specific threshold, then the ID NOW Instrument indicates that the sample is positive for the bacteria or virus that it is being tested for.
ID NOW Molecular Technology Video (Source: Abbott)
With Abbott’s Laboratories beginning to manufacture 50,000 SARS-CoV-2 cartridges per day and more and more point-of-care tests being developed by different biotech companies, we hope to be one step closer to getting widespread testing and flattening the curve to the SARS-CoV-2 pandemic.