A staff member works at a mobile coronavirus disease (COVID-19) test centre, at Burgess Park in London, Britain September 13, 2020.

Shoebox-sized coronavirus test kit could aid in winter fight against virus

Image credit: REUTERS/Simon Dawson

A portable test that aims to diagnose Covid-19 in 90 minutes could make a "huge difference" in hospitals ahead of the winter battle against the disease, scientists have said.

The test, dubbed CovidNudge, has been shown to have over 94 per cent sensitivity (the ability to correctly identify positive cases) and 100 per cent specificity (the ability to correctly identify negative cases).

Designed by DnaNudge, an Imperial College London spinout company, the test can be performed by the patient’s bedside, without requiring the use of a laboratory.

The process involves collecting nasal and throat swabs from patients and placing them onto a cartridge which goes into a shoebox-sized machine, known as NudgeBox, for analysis. It then looks for traces of genetic material belonging to the coronavirus.

Last month, the UK Government placed a £161m order for 5.8 million cartridges and 5,000 NudgeBox machines. Each machine has the ability to process up to 15 tests on the spot each day.

The blue circular CovidNudge cartridge inside the NudgeBox analyser

The blue circular CovidNudge cartridge inside the NudgeBox analyser.

Image credit: Thomas Angus/Imperial College London

Graham Cooke, professor of infectious diseases at Imperial, evaluated the results of the tests performed on 386 NHS staff and patients using CovidNudge. He described the CovidNudge testing kit as a “useful part of the whole puzzle for diagnostics”.

He explained: “[The test] is particularly well-suited for clinical settings when you are trying to make a rapid decision for a patient. For example, we had a patient from last week who had a new diagnosis of Covid.

“We were able to get the diagnosis confirmed within two hours of arriving and start distributing remdesivir and dexamethadone [drugs used to treat severe Covid-19] on that basis – much quicker than we would have been able to with confidence without that.”

The test is currently being used across eight London hospitals and is expected to be rolled out at a national level. The researchers are also making modifications to the device so the test can simultaneously assess other respiratory diseases alongside Covid-19, such as flu and respiratory syntactical virus.

“As an organisation, we are focused on using research and innovation to continuously drive improvements to care,” said Dr Bob Klaber, director of strategy, research and innovation at Imperial College Healthcare NHS Trust.

He added: “Getting accurate results back to clinicians and their patients as quickly as possible makes a huge difference to how we safely manage clinical pathways and we are very much looking forward to rolling this out more widely.”

Meanwhile, Regius Professor Chris Toumazou, chief executive and co-founder of DnaNudge and founder of the Institute of Biomedical Engineering at Imperial, said that while the test offers “very significant potential” in terms of mass testing for Covid-19, further studies are needed to demonstrate “real-world effectiveness in non-clinical settings”.

He explained: “The platform is well-suited to testing in primary care and community settings with potential for use in non-healthcare settings such as care homes, schools, transport hubs, offices and, to help bring the arts back, in theatres and venues.”

While experts have described CovidNudge as a promising development, one of the limitations is that only a single sample can be analysed at a time – this therefore may not be the answer to mass testing.

“Whether this new technology would be of value on the UK government’s Moonshot testing strategy is uncertain. The big worry is with use of any testing in asymptomatic individuals, a reported feature of this strategy,” said Paul Hunter, professor in medicine at University of East Anglia, who was not involved in the study. 

He added that any testing of asymptomatic individuals is likely to yield very low numbers of true positives – likely less than one in 10,000 tests. “When the true incidence is so low, then even a small number of false positives from a test could mean that the majority of positive results are false,” he explained. 

Hunter added that scientists would need to see much larger evaluation studies to get a better understanding of the real specificity.

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