PCR tests are the most accurate on the market but must be processed in a lab, which so far takes a few hours at minimum. When labs are overwhelmed by local surges in infection, processing can last days.
Quicker, 15-minute rapid antigen tests are less reliable than the PCR alternative.
Researchers at Fudan University in Shanghai collected nasal samples from 33 PCR-positive Covid-19 patients, 23 PCR-negative patients, six influenza-positive patients, and 25 healthy volunteers. The test accurately processed all cases without error in under four minutes, according to a peer-reviewed study published Monday, Feb.7 in the journal Nature Biomedical Engineering.
PCR tests are more precise than antigen tests because they are more sensitive. Antigen tests require a higher concentration of the virus than PCR tests to show a positive result. This means antigen tests are more likely to show a false negative.
Antigen tests seek pieces of virus-infected proteins, while PCR tests search for viral genetic material like nucleic acids and RNA.
Until now, no technology has been created to properly detect Covid-infected nucleic acids and RNA without using extraction and amplification methods, for which you need a lab environment.
The Fudan University research was conducted on a small sample, said Andrew Ching, a professor of economics jointly appointed to the Johns Hopkins Department of Economics and the Bloomberg School of Public Health.
If the 100 percent accuracy rate were to hold up in a larger test sample, Ching said, “it could be a game-changer.”