Investigators may have found a way to improve the speed, handling time, and cost of laboratory tests for coronavirus disease 2019 (COVID-19), yielding test results in just a quarter of the time required by existing gold-standard tests, according to researchers at Nanyang Technological University (NTU) at Singapore’s Lee Kong Chian School of Medicine.

The investigators said the test can be performed with portable equipment, accelerating wider adoption of COVID-19 diagnostic testing in academic or research laboratories. In particular, the test could enable screening in countries and regions with limited laboratory capabilities.

Currently, the most sensitive COVID-19 testing method uses a polymerase chain reaction (PCR) method, in which a machine amplifies viral genetic material by copying it so that any trace of the virus can be detected. Purifying RNA from other components in the patient sample creates a significant delay in testing samples, however, because it requires several hours and highly trained staff.

The new method combines many of these steps and allows direct testing on the crude patient sample, minimizing the turnaround time and removing the need for expensive RNA purification chemicals, according to the researchers.

Instead, the investigators added inhibitor-resistant enzymes and reagents targeting compounds that block RNA purification. The mix of the sample and these inhibitor-resistant enzymes is placed in a single tube, which is inserted into a laboratory thermocycler. According to a press release, the results are available after 36 minutes.

“By skipping the RNA extraction step with our direct-PCR method, we see cost savings on nucleic acid extraction kits and avoid the problem of reagent in short supply when lab testing is ramped up and the demand increases globally,” said senior research fellow Sivalingam Suppiah, PhD, in a statement.

The research team tested their method on a portable thermocycler, which can be deployed in low-resource settings and endemic areas. According to a press release, they are now looking to use the method at the NTU Clinical Diagnostic Laboratory.

“Our goal is to develop ultrafast and automated tests that yield results in minutes, and that can be performed by health care workers in the clinic with similar accuracy and sensitivity as in specialized laboratories,” said Eric Yap, PhD, in a statement. “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.”

REFERENCE
NTU Singapore researchers speed up gold-standard COVID-19 diagnostic test [news release]. Nanyang Technological University; July 27, 2020. https://media.ntu.edu.sg/NewsReleases/Pages/newsdetail.aspx?news=1ae99075-ad74-4c4b-baf1-285f9034d4f4. Accessed August 5, 2020.