Covid: how did error over wrong PCR test results in UK happen?

An estimated 43,000 people may have been given false negative results. Here are the key issues

An estimated 43,000 people may have been given wrong negative PCR Covid test results, the UK Health Security Agency (UKHSA) has said.

Here we answer key questions about the error:

What’s happened?

NHS test and trace has suspended testing operations provided by Immensa Health Clinic Ltd at its laboratory in Wolverhampton following an investigation into reports of people receiving negative PCR test results after they have previously tested positive on a lateral flow device (LFD).

NHS test and trace estimate that 43,000 people may have been given incorrect negative PCR test results between 8 September and 12 October.

Where did this happen?

The laboratory at the heart of the error is based in Wolverhampton but most of the false test results were returned to people in the south-west of England.

How serious is the problem?

UKHSA says this is an isolated incident attributed to one laboratory and the number of tests carried out at the Immensa laboratory are small in the context of the wider network, and testing availability is unaffected around the country.

But scientists have warned the error could be behind a recent rise in confirmed cases nationwide.

Dr Kit Yates, a mathematical biologist at the University of Bath, said: “We now know 43,000 people are believed to have been given false negatives, but this doesn’t even come near to the cost of the mistake. Many of these people will have been forced into school or work, potentially infecting others. This could be part of the reason behind some of the recent rises we’ve seen.”

Why did this happen?

UKHSA says “investigations are under way into the precise cause” of the mass error, adding it is looking to “determine the laboratory technical issues” behind the false negative results. The agency also says there is no evidence of any faults with LFD or PCR test kits themselves.

Who are Immensa Health Clinic Ltd?

Immensa are a private company contracted by the government to process PCR tests. The company is owned by the founder of Dante Labs, a company that started life as a DNA analysis firm. Immensa was incorporated as a company in the UK in May 2020 and by September 2020 it had been contracted by the UK government to process tests.

Its chief executive and founder, Andrea Riposati, said: “We are fully collaborating with UKHSA on this matter. Quality is paramount for us. We have proudly analysed more than 2.5m samples for NHS test and trace, working closely with the great teams at DHSC and UKHSA. We do not wish this matter or anything else to tarnish the amazing work done by the UK in this pandemic.”


Jamie Grierson

The GuardianTramp

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