Since the novel Coronavirus originated in Wuhan, China in December, scientists have developed different ways to test quickly and efficiently. At present, many test kits deliver results within three to four hours after sample collection. But that may be a thing of the past as Singapore researchers have developed a test kit that can produce results within just 30 to 40 minutes for COVID-19 as well as other viruses like dengue.
The researchers at the Nanyang Institute of Technology's (NTU) Lee Kong Chian School of Medicine uses a direct-PCR (polymerase chain reaction) method to reduce the time. In the RT-PCR or PCR method, after collecting a swab sample, the genetic material of the virus needs to be processed in a soup of chemical at a laboratory setting to amplify before testing. Although it is the gold standard, it takes a few hours to complete.
How Does It Work?
In this rapid test method, scientists have eliminated the time-consuming method of RNA (genetic material) purification. Instead, they have used inhibitor-resistant enzymes, reagents and proteins such as mucin to target compounds that prevent RNA amplification.
The swab sample is then mixed with the chemical soup and placed into a single tube which is then inserted into a thermocycler that magnifies the genetic material in PCR. After 30 to 40 minutes, the results reveal whether the sample is positive or negative for COVID-19.
Since the process involves direct testing of swab samples collected from an individual, it eliminates the need for the chemicals and saves cost.
"While polymerase chain reaction (PCR) is a venerable technology, it has some drawbacks when used outside of the laboratory environment. The process is fiddly and time-consuming. Our rapid COVID-19 test involves a single-tube reaction that reduces hands-on time and biosafety risk for lab personnel, as well as the likelihood for carryover contamination during the processing of samples," Wee Soon Keong, the first author of the paper and a PhD candidate at NTU LKCMedicine, said on Monday, July 27.
Can be Used for Dengue
The test kit, however, is not limited to just COVID-19. The same method can be used to detect other viruses and bacteria, more importantly, dengue which has been a silent killer in Singapore and Southeast Asia in the last few months. With many symptoms of dengue (like high fever, sore throat) similar to that of COVID-19, it poses a challenge to doctors. But through this rapid kit, it will be now easier to detect the presence of either of the viruses.
"We previously demonstrated that this method works for dengue virus as well. When used directly on a crude blood sample with dengue virus, the test yielded results in 28 minutes," said lead researcher Eric Yap, Associate Professor and Head of the Microbial Genomics Laboratory.
Portable and Can be Used in Any Setting
The other advantage of the method is that it can be deployed outside a laboratory and in low resource settings. Using portable thermocycler, the test kit can be used in community healthcare settings by frontline health workers.
"Our goal is to develop ultrafast and automated tests that yield results in minutes, and that can be performed by healthcare workers in the clinic with similar accuracy and sensitivity as in specialized laboratories. This will allow us to take PCR testing out of conventional laboratories nearer to the point-of-care, and into the low-resource settings that need them the most," Yap added.
The research team will use the method for COVID-19 testing at the Government-approved NTU Clinical Diagnostic Laboratory to simulate real-world settings and remove any bottleneck if there is any. The research paper was published in the Genes journal.
Last week, another group of Singapore researchers developed a similar kit that could yield result in 60 to 90 minutes. The test kit, named Resolute, eliminated the process of mixing the swab sample with chemicals to extract the RNA of the virus before placing it in a PCR machine. The kit has been developed in a joint collaboration between the Singapore DSO National Laboratories and the Agency for Science, Technology, and Research (A*STAR).
In its Reverse Transcription Polymerase Chain Reaction (RT-PCR) method, the swab sample is placed into a specifically designed pre-mixed solution before the PCR analysis. Thus, it consumes less time and results are produced fast. But the NTU-developed test kit is another leap in cutting down on time.
It remains to be seen if either of them is deployed in Singapore for testing. The Singapore Government is looking to test 40,000 people a day to curb the spread of the virus which has infected 50,838 people in the city-state, taking a toll of 27 lives.