Lab director says PCR tests can deliver accurate results despite COVID-19 variants
LOUISVILLE, Ky. (WAVE) - As the world’s battle with COVID-19 rages on, another variant has made its way into America.
According to the Associated Press, a new variant of the coronavirus emerged Thursday. The mutated version of the virus, first identified in South Africa, was found in two cases in South Carolina. Public health officials said it’s almost certain there are more infections that have not been identified yet. They are also concerned that this version spreads more easily and that vaccines could be less effective against it.
In Tuesday’s statewide COVID-19 update, Kentucky Gov. Andy Beshear confirmed two cases of the COVID-19 variant from the United Kingdom have been reported in the commonwealth.
As scientists ramp up their research, testing companies are trying to make sure their COVID-19 tests can detect the new variants.
“It has been a roller coaster,” Erik Korte said. “Nobody knew how to manage a pandemic, at least at this level, a year ago. So this is new to everybody ... patients, laboratories, physicians, we’re all just struggling to keep up.”
Korte is the laboratory director at Bluewater Diagnostics, a company that runs test sites in places throughout Kentucky. He told our sister station WAVE 3 News that despite the possible presence of a variant, PCR tests are able to deliver an accurate result, barring a few rare examples.
“That is our focus,” Korte said. “Our focus is knowing if a patient is positive or negative.”
PCR tests work by replicating RNA strands. Once the swab is taken from the nose, it’s brought to a laboratory, where technology separates a strand of RNA and converts it into DNA. Then the strand is copied several times. During the copying process, a special polymerase protein acts like Pacman and chomps its way along the strands. When it does, the DNA strand is broken down and releases a molecule.
If the molecule glows, that signifies the presence of COVID-19 and thus delivers a positive test.
Because that method of testing is layered, Korte said it’s capable of detecting a mutation in the virus, so long as the mutation is made along one gene of the code, not more. The mutation must also not be at the primer or probe site, because it may be able to avoid detection. Under both possibilities, Korte said changes can be made to the test so that it can detect the mutation.
Despite their extreme accuracy of results, Korte said the PCR test can not differentiate between the variants.
“If the variant doesn’t occur in the primer or probe region, then we can detect it, just like normal,” Korte said. “Now, we can’t differentiate. We can’t say, ‘This is the UK variant.’ We can’t say, ‘This is the wild type,’ or any of the other variants out there, but it wouldn’t hurt our ability to say this person’s positive and this person’s not.”
On Wednesday, UofL Health Infectious Disease Specialist Dr. Mark Burns said the key to fighting variants of COVID-19 is a swift vaccine rollout.
“By vaccinating people, that will keep the virus from spreading and keep it from replicating,” Burns said. “If it doesn’t replicate, it can’t mutate.”
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