User:Shawndouglas/sandbox/sublevel1

Example of a microfluidic chip used in point-of-care medical devices

On September 28, 2020, the WHO published its blueprint for what they call Target Product Profiles (TPP), which "describe the desirable and minimally acceptable profiles" for four different COVID-19 test categories.^[1] Addressing POC testing, the WHO recommends that such assays^[1]^[2]:

have a sensitivity (true positive rate) of at least 80 percent, with 90 percent or better being desirable;
have a specificity (true negative rate) of at least 97 percent, with greater than 99 percent being desirable;
provide results in less than 40 minutes, with less 20 minutes or less being desirable;
have "a cost that allows broad use, including in low- and middle-income countries";
be simple enough that only a half day to, optimally, a few hours of training are required to run the test; and
operate reliably outside a clean laboratory environment.

Though at the time of the announcement few of the available test systems could likely meet all these requirements, it's clear this and other urgencies have put pressure on manufacturers to expand COVID-19 testing to the point of care setting.^[2]^[3]^[4]^[5] Additional incentives were offered by the U.S. National Institutes of Health's Rapid Acceleration of Diagnostics (RADx) funding program, which sought to speed up innovation in COVID-19 testing and promote "truly nontraditional approaches for testing that have a slightly longer horizon."^[6] In August 2020, RADx had chosen to fund seven biomedical diagnostic companies making new lab-based and POC tests that could significantly ramp up overall testing in the U.S. into September 2020. Four of those offerings were lab-based (from Ginkgo Bioworks, Helix OpCo, Fluidigm, and Mammoth Biosciences) and three were POC tests (from Mesa Biotech, Quidel, and Talis Biomedical), all using varying technologies and methods such as next-generation sequencing, CRISPR, microfluidic chips, nucleic acid testing, antigen testing, and saliva testing.^[7] On October 28, 2020, RADx added an additional 15 biomedical diagnostics projects for funding, for a total of 22.^[8] As of September 2021, some of those 22 programs have come to fruition, garnering FDA EUAs, including Mesa Biotech's rapid cartridge-based RT-PCR Accula System, Quidel's rapid Sofia SARS Antigen FIA test, Mammoth Bioscience's SARS-CoV-2 DETECTR Reagent Kit, and Visby Medical's COVID-19 Point of Care Test.^[9]

Outside the RADx program, enterprising researchers in other parts of the world are also attempting non-traditional approaches to improving COVID-19 testing options. Examples include^[10]^[5]^[11]^[12]:

a method of DNA nanoswitch detection of virus particles;
a dual biomarker-based finger-stick test for acute respiratory infections;
a rapid breath test to detect volatile organic chemicals from the lungs;
an affordable, hand-held spectral imaging device to detect virus in blood or saliva in seconds;
an ultrahigh frequency spectroscopic scanning device to see virus particles resonating;
a method that combines optical devices and magnetic particles to detect virus RNA;
an RNA extraction protocol that uses magnetic bead-based kits;
a nanotube-based electrochemical biosensor for detecting biomarkers in a sample in less than a minute;
the additional use of an artificial intelligence (AI) application to better scrutinize test results; and
the miniaturization of PCR technology to make it more portable and user-friendly.

Of course, most of these are largely experimental technologies, and realistically getting them into the lab may be far out. But they represent out-of-the-box ideas that have some kind of chance at playing a greater role in the clinical laboratory or in point-of-care settings in the future.