Researchers develop more reliable rapid COVID-19 tests

Researchers at the University of Maryland School of Medicine (UMSOM) have developed two rapid diagnostic tests for the novel coronavirus (COVID-19) that are nearly as accurate as the gold-standard test currently used in laboratories, according to a new study published in the journal Nature Protocols.

The new tests can detect the presence of the virus within five to 10 minutes using different methods that can be performed with little training, the researchers said.

One test is a COVID-19 molecular diagnostic test, called Antisense, that uses electrochemical sensing to detect the presence of the virus. The other uses a simple assay of gold nanoparticles to detect a color change when the virus is present. Both tests were developed by Dipanjan Pan, PhD, professor of Diagnostic Radiology and Nuclear Medicine and Pediatrics at UMSOM, and his research team. They do not require the extraction of the virus's RNA, which can be both complicated and time consuming, Pan said.

Similar to the Antisense test, the second rapid test also does not require the use of any advanced laboratory techniques, such as those commonly used to extract RNA, for analysis. It uses a simple assay containing plasmonic gold nanoparticles to detect a color change when the virus is present.

Once a nasal swab or saliva sample is obtained from a patient, the nucleic acid, bits of genetic material, in the sample is amplified via a simple process that takes about 10 minutes. The test uses a highly specific molecule attached to the gold nanoparticles to detect a particular protein. This protein is part of the genetic sequence that is unique to the novel coronavirus. When the biosensor binds to the virus's gene sequence, the gold nanoparticles respond by turning the liquid reagent from purple to blue.

The new tests also are more reliable than the rapid antigen tests currently on the market, which detect the virus only in those with significantly high viral levels. Additionally, the new tests are more sensitive and can detect the presence of the virus even in those with low levels of COVID-19.

Last month, the U.S. Food and Drug Administration (FDA) registered Pan’s laboratory as an approved development site for the Antisense test. The move paves the way for Pan's laboratory to begin conducting the test at the university, in research settings, as it undergoes further development.

In February, RNA Disease Diagnostics, Inc. received an exclusive global license from UMB and UMBC to commercialize the test. Pan serves as an unpaid scientific advisor to the company. This test detects the virus in a swab sample using electrochemical sensing. It uses a unique dual-pronged molecular detection approach that integrates electrochemical sensing to rapidly detect SARS-CoV-2, the virus that causes COVID-19.

"The final prototype is like a glucometer, which patients with diabetes use at home to measure their blood glucose levels," said Dr. Pan, "and is just as easy for people to do themselves."

Dr. Pan and his colleagues, in collaboration with RNA Disease Diagnostics, are launching a study of NBA basketball players in New York City to compare the Antisense test to rapid COVID tests that the NBA is using to monitor COVID infections in its players.

"We would like to see whether our test can yield more reliable results compared to the existing platforms," he said. "Current antigen-based rapid COVID tests miss infections about 20 percent of the time and have high rates of false positive results. Our test appears to be about 98 percent reliable, which is similar to the PCR test."

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