A recent paper in The Lancet Microbe reports the first data from CovidNudge: DnaNudge’s rapid, lab-free COVID-19 test.
DnaNudge uses a SNP-genotyping technology developed by The Technology Partnership in Cambridge and explained in US10093965B2 patent. A sample is introduced into the Nudge cartridge, a disposable, sealed, and integrated lab-on-chip device, which extracts the DNA (or RNA in the case of COVID), amplifies specific targets by PCR, and applies the amplified DNA to a microchip that does the actual testing. The COVID Nudge test is now authorised by the MHRA and CE marked. The validation described on DNAnudge websote includes comparison of the COVID Nudge test to multiple PCR tests being run in NHS labs (across multiple machines: e.g. Roche, Abbott, AusDiagnostics, Cepheid and Thermo Fisher Scientific) with sensitivity of 94-98% percent, and specificity of 100%. According to the website COVID Nudge is currently being used in eight London hospitals.
The Lancet Microbe paper: Assessing a novel, lab-free, point-of-care test for SARS-CoV-2 (CovidNudge): a diagnostic accuracy study reports data from 386 samples collected between April and May, 2020 that were analysed using COVID Nudge and standard laboratory RT-PCR. 67 samples tested positive on the CovidNudge versus 71 with standard lab RT-PCR. Samples came from several groups: 280 (73%) from self-referred health-care workers, 15 (4%) from patients in the emergency department, and 91 (23%) hospital inpatient admissions.
In-vitro analysis with spiked SARS-CoV-2 RNA found the lower limit of detection to be 5 viral RNA copies per μL (this varied depending on the assay primers used) or 1 × 104 viral particles per sample. The platform was reported as having similar or greater sensitivity and specificity than other rapid assays using dry swabs.
Importantly, because the CovidNudge swabs are loaded directly into a fully sealed cartridge testing can occur outside a laboratory setting i.e. in a clinic or even in the home. And with a time-to-result of just 60-90 minutes a single Nudgebox could easily cope with a family group or social bubble in a single day.
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