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Oxford University Developing Molecular Point-of-Care Coronavirus Test

NEW YORK – University of Oxford researchers are developing a molecular diagnostic test for COVID-19 that provides results within 30 minutes and holds potential for future at-home use.  

The test, which recognizes SARS-CoV-2 RNA and RNA fragments, could be ready in a few weeks for global regulatory authorities to assess whether it can be used in clinical practice to detect the SARS-CoV-2 coronavirus, Zhanfeng Cui, one of the test's developers, said in an interview.

Using reverse transcription LAMP, an isothermal amplification technique, the diagnostic test provides results faster than RT-PCR technologies used in many diagnostic testing laboratories, Cui said. It uses a colorimetric indicator that is conjugated within a reagent to produce a visible color change in response to a positive result.

Though the group is looking to first obtain regulatory approvals for use of the diagnostic system in hospitals, it anticipates ─ after further validation ─ seeking approvals for its use in physician offices, community care centers, airports, and people's homes, Cui said.

If the researchers are successful with their clinical validation initiatives, the test could be made available at an affordable price because it uses inexpensive materials for consumables and for the instrument, he added.

Coronavirus testing is currently performed in laboratories, including hospital and reference labs, using high-throughput systems running RT-PCR tests. However, to address the need for broader testing, including settings other than hospital laboratories, companies are looking to develop tests for use at the point of care.  

"The COVID-19 pandemic has mobilized the diagnostic industry to respond, and this worldwide situation has brought to light the deficiencies of centralized testing," Andrew Wheeler, US technical lead for Mologic, said in an interview. "Simplified near-patient diagnostics enable the most effective way of screening large populations of people."

He noted that isothermal amplification technologies are being developed that advance molecular testing in decentralized settings, but "a truly integrated nucleic acid detection device does not yet exist that would allow for testing in the home or by non-technical people."  

The Oxford Suzhou Centre for Advanced Research, or OSCAR, are among organizations involved in development work for at-home diagnostics, using different technologies. Mologic initiated validation this week of its immunoassay-based lateral flow device for point-of-care applications.    

Cui is founder and director of OSCAR, the University of Oxford's first overseas research institute, located west of Shanghai. When he and fellow researchers at OSCAR decided to travel to the UK in early January, they took note of "a big contrast" between activities in China associated with the coronavirus and daily life in the UK where they were allowed easy access at London's Heathrow Airport.

"We initially wanted to create something that airports could use to quickly check on passengers when they arrived and allow them to enter the country or be put in isolation," he said.

After doing some research and development, the team recognized that the test could have broader potential and began looking for clinical samples to evaluate it. "At that time there were no positive cases for COVID-19 in the UK, so we contacted our center in China to have people who were still there get in contact with hospitals in the region," Cui said.

Cui shipped detection kits for validation to clinicians at Shenzhen Luohou People’s Hospital. The arrival of samples was delayed because of a bottleneck in deliveries caused by the outbreak, but eventually clinicians at the hospital were able to evaluate 16 clinical samples ─ eight positive for SARS-CoV-2 infection and eight negative. When they compared the test results using the LAMP test with those using RT-PCR, they found they matched.

The LAMP test has high sensitivity and can detect as little as 80 copies of viral RNA per mL of sample, Huidong Jia, a senior research scientist at OSCAR, said in an interview. "It doesn’t require specialist equipment or technical expertise, so it frees up resources and skilled healthcare workers to deliver frontline care to the worst affected."

The research group and several hospitals are working to clinically validate the test in China where OSCAR plans to apply for approval to the National Medical Products Administration. In the UK, clinicians at University of Oxford's John Radcliffe Hospital are running a validation trial using up to 200 blood samples, Cui said, adding, "We realize that we need to collect more clinical data so that we can calculate the sensitivity and specificity of the test and use the results to obtain regulatory approvals."

Cui said the LAMP technique doesn't require the same amount of time as RT-PCR to do target amplification. The technique relies on a heating block to hold test primers and sample materials at a constant temperature during isothermal amplification.

If it can be achieved, obtaining regulatory approvals for the non-professional use versions of the test could take far longer than for the professional-use version, Cui noted.

"Under normal circumstances, getting the test approved for non-professional use would take at least six months, but [in these circumstances] we don't know how long it could take," he said.

The main issue associated with home use is ensuring the user obtains a sample that enables high-quality testing, he said. "Professionals are trained to take samples from where they know there is enough virus," but with untrained users you run the risk of not having enough virus to reflect the true condition of the patient, and that could trigger a false-negative result, he said, adding that for this application, "we are mainly looking into how to take samples for home use. When you have the right sample, the home test itself is straightforward."

Cui and his colleagues join a growing number of researchers and commercial test developers who are trying to develop POC tests for detection of the coronavirus. Among those who are pursuing the same goal is Hibergene, whose assay system, a portable, battery operated device, also leverages LAMP-based testing.

Recently, a test from Cepheid became the first POC test to receive Emergency Use Authorization from the US Food and Drug Administration for the detection of the coronavirus.

Henry Schein said on Thursday that it has signed an agreement to distribute SD Biosensor's point-of-care immunochromatography test for SARS-CoV-2 in the US.

Meanwhile, the Oxford University team is investigating options for mass production of the test. Though the future price of a mass-produced consumable and instrument for the platform is unknown, achieving affordable pricing is also a prerequisite for broad acceptance, Cui noted.

In their work so far, the team has been able to use consumable materials that cost $25 per test, and the laptop-size machine needed to run the consumables costs a few hundred dollars, he added. That doesn't account for overhead expenses such as the facilities and manufacturing equipment costs, all of which have been provided for free so far by the University of Oxford, Cui said.