Researchers at UT Southwestern Medical Center have created a rapid COVID-19 test that they say can detect and identify the virus’ variants in just four hours.
In January 2021, Pathologist Jeffrey SoRelle and several of his colleagues developed CoVarScan, a rapid COVID-19 test that they claim detects the signatures of eight hotspots on the virus. Since then, the researchers have used the CoVarScan to test over 4,000 patient samples. They reported in May that their test is as accurate as other methods used to diagnose COVID-19, per a published article in Clinical Chemistry.
“Using this test, we can determine very quickly what variants are in the community and if a new variant is emerging,” said SoRelle, an assistant professor of pathology and senior author of the study. “It also has implications for individual patients when we’re dealing with variants that respond differently to treatments.”
To determine the variants of a patient’s COVID-19 infection, scientists typically use Whole Genome Sequencing (WGS), which is expensive, time-consuming, and relies on sophisticated equipment and analysis to spell out the entire Ribonucleic Acid (RNA) sequence contained in the viruses.
According to UT Southwestern, CoVarScan focuses on eight regions of the virus that differ between its variants. Each variant looks different at these hotspots. The test detects the difference between the sequence of RNA building blocks and measures the length of repetitive genetic regions that tend to grow and shrink as COVID-19 evolves.
CoVarScan, compared to WGS, had 96% sensitivity and 99% specificity, according to the study. So far, the test has identified and differentiated the Omicron (including the BA.2 subvariant), Delta, Mu, and Lambda variants of COVID-19.
“They create unique signatures, or fingerprints, of mutations,” SoRelle said, according to The Dallas Morning News. “We can really tell the difference between each of them,” he claims.
To determine the effectiveness of CoVarScan, SoRelle and his colleagues ran the test on over 4,000 COVID-19-positive nasal swab samples collected from both symptomatic and asymptomatic patients at UT Southwestern between April 2021 and February 2022. The test results were then validated with WGS, the gold standard for testing COVID-19 variants.
“A common critique of this kind of test is that it requires constant adjustment for new variants, but CoVarScan has not needed any adjustment in more than a year; it is still performing very well,” said SoRelle. “In the future, if we did need to adjust it, we could easily add as many as 20 or 30 additional hotspots to the test.”
Padmapriya Banada, a research assistant professor at Rutgers University, told DMN that the test’s ability to detect variants is critically valuable.
“It does need some technical expertise,” Banada said. “But considering what it offers, it probably overcomes those limitations.”
SoRelle is now working with Dallas County to see if CoVarScan can be used at hospitals to track the most common variants in the area. The test is already offered for use on patients who test positive for COVID-19 at UT Southwestern.
SoRelle now has a pending patent application for the test and plans on developing it for commercial use. It is not known whether his patent application is provisional or non-provisional.