False results from rapid coronavirus tests could lead to more schools closing, warn scientists
Mass use of rapid turnaround tests may have the "opposite effect" of what they are aiming to achieve because of high rates of false results, scientists have said.
False results from lateral flow Covid-19 tests may even mean that more workplaces and schools are forced to close, even though the scheme was set up to keep them open, experts cautioned.
The mass testing programme has been rolled out across the education sector, some businesses and workplaces and health and care services.
But researchers said the tests could be put to better use in different scenarios, such as by paramedics treating unwell patients and at GP surgeries.
And if the rapid turnaround tests were also used at testing centres for symptomatic people, they could also reduce contact tracing by "around three days", they added.
One academic said it was "shocking" that the Government based the mass testing on so little data.
As cases reduce in the population, a higher amount of false results will be expected and there will come a point when the testing strategy is "doing more harm than good", experts cautioned.
The comments come after a new review of the data on rapid turnaround tests.
The Cochrane Review concluded rapid tests are better at finding infections among people with symptoms than people without symptoms.
The review, which contains data from 64 studies, concluded that on average, 72% of people with symptoms who had Covid-19 were correctly identified as being infected.
In people without symptoms, on average, the antigen tests correctly identified 58% of those who were infected.
They had a higher degree of accuracy for ruling out infection.
Speaking after the publication of the review, Jon Deeks, professor of biostatistics at the University of Birmingham, and an author of the review, said the tests could be used on a "test to detect" basis but should not be used for "test to release" or "test to enable". "These performance levels show that these tests can detect - so they can work in a test to detect role - and they will probably detect around half of the cases," he said.