A quick test that detects variants comes in a few hours. How it works and what changes

The CoVarScan test is able to detect coronavirus positivity but also to identify the Covid variant: how it works and what is changing

By: VirgilioNotizie | Posted on:

A new turning point in the fight against Covid-19: Researchers fromUT Southwestern Medical Center in Dallas They announced that they created Quick testAnd the CoVarScan, Capable of detecting coronavirus positivity but also to identify the variant.

Until now, scientists have had to resort to whole-genome sequencing to identify the variant, a time-consuming, expensive and multi-day process. Now, however, the situation is changing.

What changes with the CoVarScan test

As reported by the Corriere della Sera newspaper, Jeffrey SorrellThe professor of pathology and senior author of the study published in Clinical Chemistry declared that by using the CoVarScan test “we can very quickly determine which variants are present in the population and whether a new variant is emerging.”

According to the researchers, CoVarScan could be particularly useful for monitoring the prevalence of variants and for making faster clinical decisions, particularly regarding the selection of monoclonal organisms (which act differently depending on the strain).

Pierangelo ClericiThe president of the Italian Society of Clinical Microbiologists commented: “Knowing about the spread of variants quickly is useful if the numbers are important, like now; lower if the numbers go down. We don’t know the cost of the device, so we can’t currently assess whether the cost is And the benefits will be real.”

Clerici himself added: “Today the same antiviral drugs are used to combat Covid-19 regardless of the variants. Monoclonal is an exception. However, if personalized treatments are available in the future according to the variants, the test could be very useful.”

Covid, tipping point: A rapid test that identifies variants arrives in a few hours.  How it works and what changesImage source: ANSA

A new test for Covid that identifies variants will come in a few hours.

How does the CoVarScan test work

The CoVarScan assay focuses on 8 regions of the Sars-CoV-2 genome that differ between viral variants. The test detects small mutations (in which the sequence of blocks of RNA varies) and measures the length of certain genetic regions that tend to grow or contract as the virus develops. The method relies on polymerase chain reaction (PCR), a common technique in most pathology laboratories, to transcribe and quantify RNA at these eight sites of interest.

CoVarScan’s efficacy has been tested on more than 4,000 Covid-19-positive nasal swab samples, collected between April 2021 and February 2022.

Compared with whole genome sequencing, CoVarScan showed a sensitivity of 96% and a specificity of 99%. The test successfully identified Delta, Mu, Lambda and Omicron variants, including the BA.2 version.

Limitations of the CoVarScan Test

One potential limitation of CoVarScan has to do with the fact that over the months, new types of coronavirus keep emerging and this may require constant testing update. SoRelle responded: “CoVarScan hasn’t needed any modifications in over a year and still performs very well. In the future, if we need to fix it, we can easily add another 20 or 30 test hotspots.”

Another limitation is related to the sensitivity of the test. Pierangelo Clerici explained: “In 95% of the cases tested, the intercepted viral load was high, having an infectious value, but in a significant percentage, the test also identified swabs with a very low viral load, considered non-infectious, such as positive. Even Individuals who cannot transmit the infection will test positive.”

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Image source: ANSA

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