A new low-cost, rapid diagnostic test for COVID-19 developed by Penn Medicine provides results within four minutes and is 90 percent accurate.
According to a paper published this week in Matter, the test – RAPID 1.0 (Real-time Accurate Portable Impedimetric Detection prototype 1.0) – is less expensive and more scalable, allowing for the production of millions of units per week.
Most available COVID-19 tests use RT-PCR (reverse transcription polymerase chain reaction) to detect SARS-CoV-2. Though these tests are effective, the technique requires large laboratory space and trained workers to run the tests, making them more costly, more at risk of cross-contamination, and more time-consuming, taking hours or days to get results.
RAPID quickly and accurately detects the virus while remaining inexpensive. Developed by a team led by César de la Fuente, a Presidential Assistant Professor in Psychiatry, Microbiology, Chemical and Biomolecular Engineering, and Bioengineering, the test uses an electrode printed by a screen printer to detect the virus in a nasal swab or saliva sample. Results can be read on a benchtop instrument or a smartphone.
“Prior to the pandemic, our lab was working on diagnostics for bacterial infections. But then, COVID-19 hit. We felt a responsibility to use our expertise to help–and the diagnostic space was ripe for improvements,” de la Fuente said. “We feel strongly about the health inequities witnessed during the pandemic, with testing access and the vaccine rollout, for example. We believe inexpensive diagnostic tests like RAPID could help bridge some of those gaps.”
The test uses electrochemical impedance spectroscopy to transform the binding event between the SAR-CoV-2 viral spike protein and its receptor in the human body into an electrical signal that clinicians and technicians can detect.
Using both COVID-19 positive and negative clinical samples, the team assessed samples of the highly contagious UK B117 variant. In blind tests, they analyzed 139 nasal swab samples and 50 saliva samples. The RAPID test was 87.1 percent accurate in nasal samples and 90 percent accurate in saliva samples.
“Quick and reliable tests like RAPID allow for high-frequency testing, which can help identify asymptomatic individuals who, once they learn they are infected, will stay home and decrease spread. We envision this type of test being able to be used at high-populated locations such as schools, airports, stadiums, companies–or even in one’s own home,” said first author Marcelo Der Torossian Torres, a postdoctoral researcher at Penn.
Tests cost under $5 and can be performed at room temperature.