Study finds more reliable rapid tests for COVID-19

During a recent study, researchers at the University of Maryland School of Medicine (UMSOM) developed two rapid diagnostic tests for COVID-19 that are nearly as accurate as the gold-standard test currently used in laboratories. Unlike the gold standard test, which extracts RNA and uses it to amplify the DNA of the virus, these new tests can detect the presence of the virus in as little as five minutes using different methods. The findings were published in the journal Nature Protocols. One test is a COVID-19 molecular diagnostic test, called Antisense, which uses electrochemical sensing to detect the presence of the virus. The other uses a simple assay of gold nano particles to detect a colour 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. Dr. Pan has a joint appointment at the University of Maryland Baltimore County (UMBC). "These tests detect the presence of the virus within 5 to 10 minutes and rely on simple processes that can be performed with little lab training," said Dr. Pan. They do not require the extraction of the virus's RNA - which is both complicated and time-consuming. They 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. These two newer tests are extremely sensitive and can detect the presence of the virus, even in those with low levels of the virus. Current antigen-based rapid COVID tests miss infections about 20 percent of the time and also have high rates of false-positive results. Our Antisense test appears to be about 98 percent reliable, which is similar to the PCR test." 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. 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.