Inadequate testing for Covid-19, based on poor or questionable data, is proliferating in the UK as there are no clear rules on what companies must prove before they can sell them, experts believe.
The Royal Statistical Society (RSS) has set up a task force to investigate and develop guidelines for companies performing the tests and those who evaluate and purchase them. The organization says there are “concerns about the lack of basic statistical evidence on the clinical and analytical performance of a number of new diagnostic tests available.”
The group is led by RSS chairperson Prof Deborah Ashby, as well as Prof Jon Deeks, who pointed to the failures of a number of tests. Deeks cast doubt on the claim that a government-backed antibody test by Abingdon Health is “99.4% accurate” and blasted a test from iAbra – tested at Heathrow Airport – which claimed 99.8% accuracy based on three samples.
Pinned to his Twitter account is an article titled “21 Ways to Spin Results for a Covid Diagnostic Test Accuracy”.
The working group will look at all types of tests, including the baseline swab PCR test for the virus, which is missing some of the cases. “Are we only evaluating the test as it works in the lab, or the testing process as we apply it to a real human being?” He asked.
The lab test is good, he added, but whether people get the right result depends on whether enough virus has been taken from the nose and mouth on the swab. This had to be taken into account in the performance of the test.
“That’s not to say the test isn’t working well. It’s just that we didn’t take into account the fact that it may be missing 10 or 20% of cases, just because of the sampling phase, ”said Deeks.
We might do repeated testing, he said. “In many countries, people are not allowed out of isolation until they have had two negative swabs,” he said. “Whereas in the UK we only opted for one, which is a bit out of place.” If the UK data from the tests is inaccurate, this could raise questions about the validity of the modeling.
New rapid swab, saliva, and antibody tests do not need to be approved by a regulatory body. Manufacturers are only required to certify themselves that they have met certain standards in order to obtain the CE mark. “The current CE marking system is not suitable. It does not protect the public. It allows poor and misleading tests to be marketed. It doesn’t help the government make the right decisions, ”Deeks said.