Scientists in the US have developed a rapid COVID-19 test that can accurately detect all existing types of SARS-CoV-2 within hours. The test, CoVarScan, detects the signatures of eight hotspots on the SARS-CoV-2 virus that causes COVID-19.
Researchers from the University of Texas (UT) Southwestern Medical Center in the US tested CoVarScan on samples collected from more than 4,000 patients.
Research recently published in the Journal of Clinical Chemistry shows that the test is as accurate as other methods used to diagnose COVID-19, and can successfully differentiate between all existing types of SARS-CoV-2. could.
“Using this test, we can very quickly determine which types are in the community and if a new variant is emerging,” said Jeffrey Sorrell, an assistant professor at UT Southwestern and senior author of the study.
“When we’re dealing with forms that respond differently to treatment it also has implications for individual patients,” Sorel said.
While many other tests for COVID-19 exist, they typically detect either fragments of the SARS-CoV-2 genetic material or small molecules found on the surface of the virus, and provide information to identify the type. do not provide.
In addition, many researchers worry that these tests are not accurate in detecting certain variants, or may miss future strains.
To determine which variant of COVID-19 a patient has, scientists typically must use whole-genome sequencing, which is time-consuming and costly, relying on sophisticated equipment and analyzes to The complete RNA sequence contained in the virus can be traced.
CoVarScan works on eight regions of SARS-CoV-2 that typically differ between viral variants.
It detects small mutations – where the sequence of RNA building blocks differ – and measures the length of repetitive genetic regions that grow and shrink as the virus evolves.
The method relies on polymerase chain reaction (PCR) — a common technique in most pathology labs — to copy and measure RNA at these eight sites of interest.
SoRelle’s team ran the test on more than 4,000 COVID-19-positive nasal swab samples collected at UT Southwestern from April 2021 to February 2022 – from both asymptomatic and asymptomatic patients.
The tests were validated with gold-standard whole genome sequencing, and the results were used by doctors to select treatments in some critically ill COVID-19 patients.
Compared to whole genome sequencing, CoVarScan had 96 percent sensitivity and 99 percent specificity.
It identified and differentiated delta, mu, lambda and Omicron variants of COVID-19, including the ba.2 variant of Omicron, once known as the “stealth Omicron”, as it was the only Omicron strain. did not appear on some tests designed to detect ,
“A common criticism of this kind of testing is that it requires constant adjustments for new variants, but CoVarScan hasn’t needed any adjustments in more than a year; it’s still performing very well, SoRelle said.
“In the future, if we need to adjust this, we can easily add 20 or 30 additional hotspots to the test,” he said.
SoRelle plans to continue developing CoVarScan as a commercial test and has a pending patent application based on this work.