Health and Safety Breaches at the Milton Keynes Lighthouse Lab
by Julian D. Harris PhD A great deal of pressure has been placed on the polymerase chain reaction (PCR), the assay used to determine the prevalence of COVID-19 cases. The UK government have invested heavily in several Lighthouse labs for COVID-19 testing, but there have been a growing number of concerns about the reliability of these tests. There’s a concern that the PCR assay may be inflating the number of COVID-19 cases by generating false positives. What Causes False Positives in COVID-19 Testing The PCR is an extremely sensitive and specific assay that inevitably generates a certain proportion of false positives. Apart from the well-documented false positive rate – whereby ~0.8% of people tested will be falsely designated as positive, even when the test is run perfectly – there are also false positives generated by the test’s over-sensitivity, whereby if you’ve had COVID-19, or another coronavirus, but are no longer infectious, you may still be shedding small components of the virus and test positive. That risk increases as the number of amplification cycles increases. But there is a third cause of false positives which is when cross-contamination takes place between the samples being tested, so a positive sample can contaminate a negative one, turning them both positive. That’s the risk I want to flag up in this article. My Time as...
