Standard PCR tests do not pick up new Covid strains, warns expert

Some new strains of Covid-19 are not being picked up by standard PCR tests, reveals leading testing expert Dr Quinton Fivelman. He warns that new mutations mean some variants are not being picked up by the standard, widely-used, single gene tests.

The PCR (polymerase chain reaction) blood test is considered the ‘gold standard’ in detecting Covid-19 infections. However, one of the UK’s leading experts in Covid-19 testing, Dr Quinton Fivelman PhD, claims some strains of the virus have now evolved in a way that evades detection by many standard PCR tests.

Dr Fivelman, the Chief Scientific Officer at London Medical Laboratory, says: ‘Scientists have noted some variants of the Covid-19 virus are not being detected by the traditional PCR test, which is considered superior to the quicker and less sensitive lateral flow test. Changes to the SARS-CoV-2 genomes – including some of those found in currently circulating variants – mean that key virus genes have altered so significantly that they can muddle PCR tests and give the wrong result.

‘Scientists in France and Finland first noted that some Covid-19 mutations were evading detection earlier this year, and now new strains have been found in the UK that are not being picked up using the traditional tests. Standard PCR tests that just target one specific gene may not detect these variants if the gene has even slightly altered.

‘London Medical Laboratory’s PCR test targets two Covid-19 genes: nucleocapsid (N2) and envelope (E). Last month alone, we had three patient samples that tested negative for the N gene but positive for the E gene. Had the test just been focused on the N gene, the cases would have gone undiscovered and these people would have returned to work, potentially infecting others with undetectable Covid-19.

‘There is growing concern that traditional single gene PCR tests used by many hospitals to diagnose Covid-19, and to ascertain if people are “fit to fly”, could be missing cases, leading to the increased spread of the virus and cases going untreated for too long.

‘London Medical Laboratory is calling on all testing facilities to adopt tests targeting at least two genes immediately, to ensure the UK can continue to treat patients effectively and retain an accurate picture of the number of cases there are in the community. If too many cases go undetected, the Government’s entire plan to contain the virus this winter will the thrown into jeopardy and we could see the return of lockdowns.’

If anyone is concerned about the accuracy of their recent PCR test, they can take London Medical Laboratory’s two-gene PCR test. This is available from our drop-in clinics, at home via the post, or through a home visit from one of our qualified phlebotomists."

Dr Fivelman, Chief Scientific Officer, London Medical Laboratory