AsianScientist (Mar. 20, 2020) – All over the world, countries are sinking into a public health crisis as the COVID-19 outbreak develops into a global pandemic. Highly infectious, the coronavirus SARS-CoV-2 can spread from person to person even before symptoms appear. Accurate, widespread diagnosis is therefore critical to curbing new viral outbreaks, allowing infected individuals to be identified and quickly quarantined to stop the train of transmission.
South Korea, one of the first countries to experience the epidemic outside China, has shown that widespread testing might be a good solution to contain the virus. The country’s elaborate testing program, which saw more than 270,000 people tested thus far, has helped to slow down the influx of new cases since its record high of 909 cases on February 29, 2020.
Unfortunately, not all countries have the capacity to test for the virus on a nation-wide scale. Part of the reason is the shortage of diagnostic kits. As the infection rate increases, some diagnostic services find it difficult to keep up with the rising demand for tests.
To support medical efforts on the frontline, JN Medsys, a Singapore-based life sciences company, released ProTect™, their latest COVID-19 diagnostic kit. According to Mr. Johnson Ng, founder and CEO of the company, the product has received provisional authorization for in vitro diagnostic use from the Singapore’s Health Sciences Authority and is ready to be shipped. Speaking about the development of ProTect™, Ng also describes how the products they developed address current gaps in the COVID-19 crisis.
- How does the ProTect™ kit work? What is JN Medsys’s production capacity for this kit?
- How did the development of the ProTect™ kit begin? What were some of the key considerations during the process?
- How is JN MedSys’s approach to designing diagnostic kits for COVID-19 unique?
- How do diagnostic kits like Clarity™, which is based on digital PCR, work?
- What are some issues that remain unresolved in detecting SARS-CoV-2? How do both kits address these issues?
The ProTect™ COVID-19 kit is based on real-time polymerase chain reaction (RT-PCR) technology, the standard method for detecting SARS-CoV-2. Our kit is designed to detect for three targets in the N gene of the virus, which is in accordance to the protocol laid out by the Centre for Disease Control and Prevention (CDC) in the United States. At the moment, we produce 20,000 kits per week, but can bring this capacity up to 50,000 kits if necessary.
We decided to develop ProTect™ because we received an order asking if we could supply a large number of COVID-19 test kits within a short period of time. Although we have never sold any diagnostic kits based on real-time PCR before, we have designed and manufactured similar kits for digital PCR. The whole process took us two weeks.
Some of the main considerations we had during development were related to the tight deadline and scale of our production. Not only did we have to streamline the entire product development process, but we also needed to ensure that the kit’s performance was robust. Furthermore, we had to resolve supply chain issues for manufacturing to proceed smoothly.
Right now, most diagnostic kits testing for COVID-19 are based on RT-PCR technology, like our ProTect™ kits. However, we have also developed another kit, Clarity™, which uses a different approach called digital PCR.
Unlike real-time PCR, digital PCR can provide more accurate diagnoses due to its improved sensitivity and precision. This is because digital PCR uses absolute quantification (as opposed to relative quantification—which RT-PCR uses). The method of calculation enables our Clarity™ kits to quantify very low viral loads where conventional methods fail. This capability is especially useful as it provides valuable insights into a patient’s health during recovery and treatment. Our Clarity™ kit detects for Orf1ab, N1 and N2 genes in SARS-CoV-2, following China’s diagnostic protocol.
Unlike the ProTect™ kit, which only detects a single target in each reaction, our Clarity™ kits can detect two targets simultaneously (duplex detection). This means that the total number of reactions for the Clarity™ kit could be doubled for each sample.
Digital PCR is a highly sensitive and precise next-generation PCR technique for detecting genetic material like DNA. Although it uses the same reaction components as conventional PCR, the main difference is that digital PCR partitions its sample into thousands of sub-reactions that contain only a single copy of DNA. That way, by counting the number of successful reactions after PCR, the number of DNA copies in the sample can be quantified.
Even though RT-PCR technology remains the gold standard for detecting SARS-CoV-2, users have reported inaccurate or inconsistent results, such as false negatives. For example, RT-PCR has difficulty detecting samples at low abundance and is also easily affected by contaminants that carry over from the sample preparation process, which can contain inhibitors that affect the kit’s accuracy.
Our digital PCR kits, on the other hand, are more resistant against inhibitors and more sensitive—especially for samples at low abundance. While RT-PCR remains a mature technology that works well in most cases, digital PCR kits like ours present a suitable alternative when current standards for viral detection falls short.
Copyright: Asian Scientist Magazine; Photos: JN Medsys.
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