Technology gaps that have hindered previous efforts to develop at-home diagnostic tests are starting to fill in, thanks to COVID. Excerpted from MedTech Strategist's feature on the NIH RADx program.
While the Rapid Acceleration of Diagnostics Initiative (RADx), formed by the National Institutes of Health in April 2020, has a broad mandate to address all kinds of COVID-19 diagnostic testing bottlenecks, longstanding technology gaps that have hindered previous efforts to develop high-quality, rapid, near-patient and home tests for many diseases need resolution. This has been a particular hurdle for rapid antigen tests, which are key to mass testing strategies aimed at keeping the virus at bay over the long run in public places.
The new crop of FDA Emergency Use Authorized rapid near-patient and home tests that are coming on the market now do that to some extent, and it will be interesting to see if their advances carry over to accelerate the broader home testing market beyond COVID-19, says Todd Merchak, a biomedical engineer and program specialist at the National Institute of Biomedical Imaging and Bioengineering, who is working closely with RADx participants on these initiatives. Their efforts are the confluence of scientific advances in many areas ranging from optical imaging for detection to computational and artificial intelligence methods that improve antibody identification and selection.
Each company in the RADx program is taking a different approach to adjusting the many components of the testing technology that affect performance, with the goal of optimizing signals that obtain the lowest levels of detection. On the front end this could include tinkering with the sample collection process—including the type of sample, rinses and washes, dilution, and transport.
On the analytical end, it might drive the selection of the type of antibody binding chemistry that enables detection of all levels of virus in a medium, the fluorophore selection, and how fluid flows through a device. “All of this impacts the ultimate level of detection that achieves optimal sensitivity,” Merchak says. There has been improvement in antibody pairing driven by the application of computational mathematics and artificial intelligence to the selection process. That has been crucial because “if you had to bench-test all your antibodies, it would take years,” he says.
Nanotech and microfabrication advances also play a role, as each company vying for an EUA for rapid diagnostic testing has its own detection reader, chip design, and materials that allow fluid to flow through at the right rate. Some companies select fluorophores that use nanotech approaches to make brighter probes, for example, he says.
As for sample type and handling, that matters more than people realize, he continues. Already nasal swabs are easier to use and more comfortable. That said, the ideal sample for home testing is saliva, which so far is not yet ready for prime time, but RADx companies are “making headway and we are hopeful that such tests will be available later this year.”
Excerpted from “What the NIH RADx Program Means for Rapid, At-Home Testing Beyond COVID-19,” MedTech Strategist, April 14, 2021.
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