Estimated 43,000 people could have had false negative Covid PCR test results

An estimated 43,000 people may have been told they didn't have Covid-19, when they did.

The error is down to issues with Covid PCR tests processed at one lab in Wolverhampton which has now been shut as NHS Test and Trace investigates reports of people receiving negative PCR results despite testing positive on a lateral flow.

NHS Test and Trace estimates around 400,000 samples have been processed through the lab, operated by Immensa Health Clinic Ltd, and the vast majority of these were given negative results.

The potential false negatives were all in the period September 8 to October 12 and were mostly in the south west of England but people in the south east and Wales have also been impacted.

Despite tens of thousands of results potentially being wrong, officials have said the issue is "an isolated incident attributed to one laboratory".



An estimated 4,000 of the more than 40,000 impacted were in Wales, with the majority of these tests taking place across the Gwent and Cwm Taf Morgannwg areas, the Welsh Government said.

One test centre, Newbury Showground site in West Berkshire, has confirmed tests it sent are also among the 43,000 involved.

The testing error happened during a period when Covid cases had been rising exponentially among pupils as schools reopened in September.

NHS Test and Trace is now working to contact people who could still be infectious despite their negative test result.


Coronavirus: What you need to know


ITV News had already spoken to people reporting issues with testing before Friday's announcement.

One woman got a negative result for Covid-19 after using a PCR test - but she ended up being admitted to Musgrove Park Hospital with both Covid and pneumonia after her symptoms worsened.

Trish Caller said: : "I’ve lost all my trust in the testing. Why don't these tests pick up Covid?"

A mother in Somerset, Gemma Tyson, fears her son Ashton may have received a false negative PCR test result that allowed him to return to school.

Ashton had 10 positive lateral flow test results but three negative PCRs. He returned to school on September 8 but developed Covid symptoms three days later, including a headache and loss of appetite.


PCR tests require lab analysis meaning they take longer to process. Credit: PA

What does the latest Covid data show about cases in the period impacted?

The latest Office for National Statistics (ONS) figures showed around one in 15 children in school years seven to 11 in England are estimated to have had coronavirus in the week to October 2.

A separate study, conducted by Imperial College London and Ipsos Mori between September 9 and September 27, suggests one in 120 people were infected.

According to the study, the infection rate is growing among under 18s and falling among adults.


The Welsh Government said it was first made aware of the issue last week, with a number of cases from south Wales.

Eluned Morgan, MS Minister for Health and Social Services, said: "My immediate concern is the information and support for the Welsh residents impacted and I have asked Public Health Wales to provide additional support and advice to the affected health boards in addition to the UK Health Security Agency communications.

"They will also be assessing the potential impact of this incident on the case rates and epidemiology reports for Wales."

A Covid-19 drive-through test centre for NHS workers in Wembley, north-west London Credit: Jonathan Brady/PA

West Berkshire Council said some of the tests at the Newbury Showground site “have had results sent out that may have incorrectly shown as negative for Covid-19”.

It added: “After receiving reports from local residents in recent weeks that there were concerns about the accuracy of test results from the site, we passed these concerns onto the DHSC for further investigation.

“The DHSC has now confirmed that a number of sites nationally may have been affected by this issue, including the one at Newbury Showground.”

Those who received a negative result for a PCR test between October 3 and 12, as well as their close contacts, are “strongly” encouraged by the local authority to take another test.

Discrepancies in the results of lateral flow and PCR tests have meant people are being advised to self-isolate if symptomatic Credit: ITV West Country

Dr Will Welfare, public health incident director at UK Health Security Agency, said: “We have recently seen a rising number of positive lateral flow device results subsequently testing negative on PCR.

"As a result of our investigation, we are working with NHS Test and Trace and the company to determine the laboratory technical issues which have led to inaccurate PCR results being issued to people."

He said there is no evidence of faults with lateral flow tests or PCR test kits.

Andrea Riposati, CEO of Immensa Health Clinic Ltd, said the company is "fully collaborating with UK Health Security Agency on this matter.

"We do not wish this matter or anything else to tarnish the amazing work done by the UK in this pandemic," she added.

The blow to trust in testing also comes as ministers announced fully vaccinated people arriving in England from countries not on the coronavirus travel red list can take a lateral flow test rather than the PCR version from Sunday, October 24.