Covid-19 or dengue? NTU researchers develop method that gives results in just 36 minutes

A team of researchers consisting Associate Professor Eric Yap, PhD candidate Mr Wee Soon Keong and senior research fellow Dr Sivalingam Paramalingam Suppiah have demonstrated a way to improve the speed, handling time and cost of Covid-19 laboratory tests.
PHOTO: NTU Lee Kong Chian School of Medicine

SINGAPORE - Researchers at the Nanyang Technological University (NTU)'s Lee Kong Chian School of Medicine have come up with a way to tell if a person has Covid-19 or dengue in just 36 minutes.

This is just one quarter of the time taken by current testing methods for the same diseases, NTU said on Monday (July 27).

At the moment, the most sensitive way to detect Covid-19 is through a polymerase chain reaction (PCR) technique in a laboratory, which uses a machine to "amplify" viral genetic material by copying it over and over again so any trace of the Sars-CoV-2 virus, which causes Covid-19, can be detected.

But while such a method is accurate, it can take a few hours to complete, partially due to a step known as RNA purification.

When a patient is swab tested, their RNA needs to be extracted from the swab sample to remove any substances in the sample that inhibit the PCR test from working, such as mucin - a main component of mucus.

It also requires chemicals that are now in short supply worldwide, and needs to be carried out by highly trained staff using expensive equipment.

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But the NTU team's method, known as "direct-PCR", uses a series of commercially available enzymes and reagents that are resistant to inhibitor substances to overcome this obstacle.

By mixing them together with patient swab samples in a test tube, the team is able to skip the RNA purification step and perform the test on the sample directly, producing accurate results in a shorter time.

Dr Sivalingam Paramalingam Suppiah, a senior research fellow who was part of the team, said: "By skipping the RNA extraction step with our direct-PCR method, we see cost savings... and avoid the problem of reagents in short supply when lab testing is ramped up and the demand increases globally."

The team's method can also be deployed outside of a laboratory using a machine known as a portable thermocycler.

PhD candidate Mr Wee Soon Keong with portable equipment that allows the test to be deployed in the community, outside of a lab setting, as a screening tool. PHOTO: NTU LKCMEDICINE  

This means there is a possibility that its testing method can be used in community healthcare settings by front-line healthcare workers, rather than needing to send the results to a laboratory and wait for them to be processed there.

The team's leader, Associate Professor Eric Yap, noted that further studies need to be done to see how effective the test method is in a real-world setting.

"When one bottleneck is removed, other challenges may emerge, like ensuring quality control, or reducing manual errors," he said.

They are currently aiming to use the method in Covid-19 testing at the NTU Clinical Diagnostic Laboratory.

Prof Yap added that the team's method works on the dengue virus as well, producing results in just 28 minutes.

PhD candidate Mr Wee Soon Keong preparing a patient's sample using the team's method before it is tested. PHOTO: NTU LKCMEDICINE

"As Singapore battles the dual outbreak of dengue and Covid-19, both with similar early symptoms, our test could help in differentiating between the two infectious diseases," he said.

He added: "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 specialised 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."

This article was first published in The Straits Times.

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