Covid-19: What is the UK’s testing strategy?
Gareth Iacobucci
Abstract
The NHS is using polymerase chain reaction (PCR) testing to determine which people currently have covid-19. This involves extracting RNA from a nose or throat swab sample through laboratory analysis. It has a high level of accuracy, and results take around a day to come through. But once a person has recovered the test can no longer tell if they have been infected. The other type of test, which Public Health England (PHE) says could be available to UK residents to use at home “within days,” subject to testing, detects antibodies in the blood. This test is designed to detect whether someone previously had the virus. Blood or plasma samples are inserted into a small plastic cassette-shaped device, and results are typically ready within 10 minutes. Aside from the speed of obtaining results, the UK’s chief scientific adviser, Patrick Vallance, said that antibody tests had the advantage of being able to detect infection in people without symptoms. But the tests are less sensitive and specific than PCR tests, so can produce more false positives and false negatives. Patients in hospital intensive care units with suspected covid-19 have been first priority, followed by people with severe respiratory illness such as pneumonia. The next priority has been isolated cluster outbreaks, …