Singapore scientists find out rapid COVID-19 test method  (//www.straitstimes.com/)

Singapore (VNA) - Scientists at the NanyangTechnological University (NTU) of Singapore on July 27 discovered a way todeliver coronavirus testing results within 36 minutes, about a quarter of thetime required by existing gold-standard tests.

Currently, the most sensitive method of testing for the coronavirus is througha laboratory technique called polymerase chain reaction (PCR), where a machineamplifies genetic material by copying it over and over again so any trace ofthe coronavirus can be detected.
A big problem is purifying the ribonucleicacid (RNA) from other components in the patient sample – a process thatrequires chemicals that are now "in short supply worldwide”, NTU said.

“The method developed by NTU LKCMedicine combines many of these steps andallows direct testing on the crude patient sample, cutting down the turnaroundtime from sample-to-result, and removing the need for RNA purificationchemicals,” the university added.

In PCR tests, the genetic material on the swab sample has to be extracted toremove substances in the sample that prevent the test from working. One exampleof an inhibitor is mucin, a main component of mucus.

The test designed by the NTU team uses the“direct PCR method”, but removes the need for RNA purification – atime-consuming and costly step.

“Instead, they addedinhibitor-resistant enzymes and reagents targeting compounds that obstruct RNAamplification, such as mucin … these enzymes and reagents, which arecommercially available, have high resistance to such compounds that otherwiseinhibit PCR, rendering the test inaccurate," said NTU.

The biochemical mix of crude sample and inhibitor-resistant enzymes andreagents is placed into a single tube, which is inserted into a laboratorythermocycler, a machine used to amplify genetic material in PCR. After 36minutes, results reveal whether there is any trace of COVID-19 “withconfidence”.

The team also tested this method on a portablethermocycler, which can be deployed in low-resource settings and endemic areas,pointing to the possibility of having this test done in community healthcaresettings by frontline healthcare workers.

𒀰 Senior research fellow Dr SivalingamParamalingam Suppiah said: “By skipping the RNA extraction step with ourdirect-PCR method, we see cost savings on nucleic acid extraction kits, andavoid the problem of reagents in short supply when lab testing is ramped up andthe demand increases globally.”/.