Published: 17 September 2020
A 90-minute on-the-spot test for COVID-19 that is performed in a device smaller than a mobile phone has been shown to be highly accurate, in new research supported by the NIHR.
The Lab-in-Cartridge rapid testing device, which does not require sending samples away to a laboratory for analysis, produced very few false negatives and no false positives.
The test uses a paediatric-sized nose swab from a patient that is analysed for traces of genetic material belonging to the SARS-CoV-2 virus in a cartridge smaller than a mobile phone. Results are available within 90 minutes, compared to 24 hours for conventional COVID-19 tests.
The new research assessed the high-speed test on 386 NHS staff and patients. The results, published in the journal Lancet Microbe, show that the test had over 94% sensitivity and 100% specificity.
The test is currently being used successfully across eight London hospitals, following initial validation and authorisation by the Medicines and Healthcare Products Regulatory Agency (MHRA), and is due to be rolled out at a national level. The UK government recently placed an order for 5.8 million of the testing kits.
Professor Graham Cooke, lead author of the study at Imperial College London and an NIHR Research Professor, said: “These results suggest the test, which can be performed at a patient’s bedside without the need to handle any sample material, has comparable accuracy to standard laboratory testing.
“Many tests involve a trade-off between speed and accuracy, but this test manages to achieve both. Developing an effective bedside test in under three months has been an incredible collaboration between teams of engineers, clinicians and virologists.”
The testing device, produced by DnaNudge, an Imperial start-up headquartered in White City, was used on 280 NHS staff members with suspected COVID-19, 15 patients in A&E with suspected COVID-19, and 91 hospital inpatients (some of who were not displaying COVID-19 symptoms).
The samples from all individuals in the study were analysed on both the rapid-testing device, called the CovidNudge test, and standard hospital laboratory equipment - and then the results compared.
The research team, which included scientists and clinicians from Imperial, Imperial College Healthcare NHS Trust, DnaNudge and Oxford University Hospitals NHS Trust, assessed the sensitivity and specificity of the test.
Sensitivity is a measure of how well a test gives a positive result for people who have disease, and is an indication of how likely a test will produce false negative results. Specificity, on the other hand, is a measure of a test’s ability to give a negative result for people who don’t have the disease, and is an indication of the likelihood of false positive results.
The percentage of people found to be positive for COVID-19 was 18% (the study was conducted in the peak of the pandemic in April and May 2020). The results showed 67 samples tested positive on the CovidNudge test, compared with 71 positive results against a range of NHS standard laboratory machines, which represents the value of 94% sensitivity.
The research was supported by the NIHR Imperial Biomedical Research Centre, NIHR London In vitro Diagnostics Co-operative and the NIHR Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance.
Regius Professor Chris Toumazou, CEO and co-founder of DnaNudge and founder of the Institute of Biomedical Engineering at Imperial, said: “The DnaNudge test was developed as a lab-free, on-the-spot consumer service that can be delivered at scale, so we clearly believe it offers very significant potential in terms of mass population testing during the COVID-19 pandemic.
“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, theatres and venues. However, further studies of real-world effectiveness in non-clinical settings would be required prior to widespread deployment.”
The research team added the device recently obtained a CE mark, enabling its additional use in non-clinical locations (it has been previously approved by the UK Medicines and Healthcare Regulatory Agency).