As the government prepares to end most free Covid testing on 1 April, experts tell CSW the validation process for commercial tests is failing to ensure they are sufficiently reliable, or to enable people to make informed choices about which tests to buy

Experts have implored the government to take urgent steps to ensure Covid tests being sold in the UK are reliable, months after the UK Health Security Agency warned that poor-performing tests could present a public health risk.

Following the announcement that free Covid testing will end in England on 1 April, experts have told CSW  that the current validation scheme for private tests fails to ensure tests are sufficiently reliable, or to enable people to make informed choices about which tests to buy.

Lateral flow and PCR tests being sold for general use in the UK do not have to meet the same rigorous standards as tests bought by the Department for Health and Social Care to be distributed through GOV.UK and pharmacies.

Last summer, UKHSA said it would bring in a “gold-standard” validation scheme by the end of 2021 to "rapidly increase quality in the private market to at least the same baseline as those procured for the NHS".

In June, it confirmed plans to tackle “public health risks posed by poor-performing Covid-19 tests on the market” with a two-step scheme that would require manufacturers of paid-for Covid tests to pass a desk-based review, before submitting tests for independent assessment in a laboratory.

Any tests that failed either stage of the two-step process would be barred from the market.

UKHSA introduced the desk-based review in July, before which, manufacturers could use a CE mark to self-certify that their tests met the minimum standards.

But it has still yet to introduce a requirement for independent lab-based testing to ensure manufacturer’s claims about the reliability of their tests are correct.

Lack of independent lab validation 'very, very worrying'

Prof Azeem Majeed, head of Imperial College London’s Department of Primary Care and Public Health, says proper validation of Covid tests is “essential” to ensure that tests “give accurate results with good sensitivity and specificity, and a low risk of false negative or false positive results”.

“This will become even more important once free testing is scaled back in England from April onwards, when many more people will be relying on commercial Covid-19 tests,” he adds.

“This will become even more important once free testing is scaled back in England from April onwards, when many more people will be relying on commercial Covid-19 tests"

Indeed, UKHSA – which runs NHS Test and Trace as well as setting testing standards – said last summer that without the validation process, there was a higher risk of private tests producing both false positives and false negatives.

The rigorous validation scheme UKHSA uses to assess tests distributed through NHS Test and Trace has exposed "consistent disparities between manufacturers’ claims… for their devices and the actual performance of those devices", according to an October impact assessment published last week.

Three-quarters of LFTs UKHSA assessed for NHS Test and Trace failed to meet the required standard, the impact assessment said.

“Whilst the DHSC can procure the test products that it wants and control which products it uses, this data and expertise is not easily available to the public and institutions when they are looking to find the right test to use,” it warned.

The desk-based assessment it introduced in July – which involves an inspection of documents manufacturers provide as evidence that their tests meet UKHSA’s minimum standards – went only part of the way towards resolving this. 

“Whilst the DHSC can procure the test products that it wants and control which products it uses, this data and expertise is not easily available to the public when they are looking to find the right test to use" –UKHSA

According to its June plan, UKHSA said lab validation would be used to “ascertain [tests’] specificity, sensitivity and limits of detection”.

Lawrence Young, a virologist and professor of molecular oncology at University of Warwick, says it is “quite clear” a two-step validation process including laboratory testing is needed.

“You absolutely need to have technical validation,” he tells CSW. “It's one thing to go through a paper-based exercise to demonstrate what you've done as a company, in terms of that desktop review. But you really do need to compare and contrast [tests’ performance].

“Messing around with people’s health in this way is very, very worrying.”

Deepti Gurdasani, a clinical epidemiologist and statistical geneticist at Queen Mary University of London, says it is “unacceptable that validation and vetting of quality standards is not a requirement for something as important as testing for Covid-19 – where errors can cost lives”.

Prof Gurdasani said the consequences of errors in Covid testing were seen in the Immensa scandal last year, where thousands of people were given false negatives on PCR tests processed in a lab that won a DHSC contract. She said those errors “no doubt led to onward transmission from those falsely reassured and, sadly, possibly even hospitalisations and deaths as a result”.

Public 'has a right to expect' data on tests' performance

As well as ensuring quality, the validation process was intended to generate data on the performance of each commercial Covid test, which would be shared on a public register that people could use to decide which to buy.

There is currently a list on GOV.UK of private providers that have passed UKHSA’s desk-based review – but this includes no performance data.

Prof Sheila Bird, a programme leader at the MRC Biostatistics Unit at the University of Cambridge, says the public “has a right to expect” data on tests’ performance that they can use to decide which to buy.

“It is extremely important that those data are not hidden away from the citizen,” she says. “There is a need now – or certainly prior to April – for all such evaluation data to be put into the public domain so that the public, when they are allowed to choose which seven-pack [of LFTs] to buy, have a basis for making the choice.”

Young from the University of Warwick agrees that “you need some way of ensuring that the public understand what they're buying, rather than a free-for-all type of marketplace”.

He also warned that if minimum standards are not strictly enforced, "there is also a real concern" that people could become forced to choose between more reliable but expensive tests, and cheaper but less reliable ones.

"Is there going to be a way of regulating the costs of these things? Or is it going to be a Wild West? That really worries me because you can't play games with people's health."

“You need some way of ensuring that the public understand what they're buying, rather than a free-for-all type of marketplace”

Opening its consultation on the validation scheme last year, UKHSA said a lack of transparency over test performance – with consumers forced to make decisions based on “suboptimal, unstandardised data” – made it difficult for people to compare tests.

A publicly-available register with “clear and comparable information on each test’s performance” would “replace the current confusion consumers face when purchasing… with a more equitable marketplace”, according to the October impact assessment.

It added that improved test performance could boost consumers’ confidence, and therefore drive up participation in testing.

Why the delay?

The October impact assessment revealed that the policy had been delayed because DHSC's attempts to procure a laboratory group to carry out the validation process had failed to find a bidder that could meet the required standards.

The government’s “Living with Covid” plan, following the PM’s announcement on the ending of restrictions and plans to end mass free testing by 1 April in England, makes no explicit reference to the validation process.

CSW submitted a series of questions to UKHSA, asking why it had not introduced a requirement for lab-based assessment of commercial tests after repeatedly stressing the urgency of doing so – and whether strengthening validation of private tests is still considered a priority.

Responding to CSW’s queries, a UKHSA spokesperson said: “Testing will continue to be an important tool in managing Covid-19 and there are comprehensive regulations in place to ensure that the public can have full confidence in the tests they buy.

“The Coronavirus Test Devices Approval process is one of the most rigorous in the world and ensures that tests on the market in the UK meet strict quality standards.”

Further updates to the approval process will be provided in due course, they said.

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