New Rapid COVID-19 Diagnostic Tests Use Innovative Techniques that Improve Accuracy Rivaling Gold Standard PCR Test

Researchers have 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 developed by researchers at University of Maryland School of Medicine (Baltimore, MD, USA) can detect the presence of the virus in as little as five minutes using different methods. They do not require the extraction of the virus's RNA - which is both complicated and time consuming. Both tests are more reliable than the rapid antigen tests currently on the market, which detect the virus only in those with significantly high viral levels.

One test is a COVID-19 molecular diagnostic test, called Antisense that uses electrochemical sensing to detect the presence of the virus. The test detects the virus in a swab sample using an innovative technology called electrochemical sensing. It uses a unique dual-pronged molecular detection approach that integrates electrochemical sensing to rapidly detect the SARS-CoV-2 virus.

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.

"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 Dipanjan Pan, PhD, Professor of Diagnostic Radiology and Nuclear Medicine and Pediatrics at UMSOM. "These two newer tests are extremely sensitive and can detect the presence of the virus, even in those with low levels of the virus."

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University of Maryland School of Medicine