Biosensor Image
RAPID, a low-cost COVID-19 diagnostic test, can detect SARS-CoV-2 within four minutes with 90 percent accuracy. (Credit: Penn Medicine)

A low-cost, rapid diagnostic test for COVID-19 provides COVID-19 results within four minutes with 90 percent accuracy. Compared to existing methods for COVID-19 detection, the fast and inexpensive diagnostic test, called RAPID 1.0, is inexpensive and highly scalable, allowing the production of millions of units per week.

An electrode printed using a screen printer — thousands of which can be printed in a day at very low cost — can detect the virus in nasal swab or saliva samples. The results can be read on a benchtop instrument or on a smartphone.

The RAPID technology uses electrochemical impedance spectroscopy (EIS), which transforms the binding event between the SARS-CoV-2 viral spike protein and its receptor in the human body, the protein ACE2 (which provides the entry point for the coronavirus to hook into and infect human cells), into an electrical signal that clinicians and technicians can detect. That signal allows the test to discriminate between infected and healthy human samples. The signal can be read through a desktop instrument or a smartphone.

RAPID provides results in four minutes, which is faster than most methods currently available for diagnosing COVID-19. For example, serological tests can take around 15 to 20 minutes, and they are about 60 to 70 percent accurate. In addition, RAPID is able to detect COVID-19 at extremely low concentrations (1.16 PFU mL), which corresponds to a viral load that correlates with the initial stages of COVID-19 (about two to three days after onset of symptoms). This is beneficial for detecting individuals at the earliest stages of infection, allowing for rapid care and the potential decrease of further viral spread.