Many negative PCR test results in the South West, 8th Sept – 12th Oct, may have been inaccurate

Summary: Between 8th Sept and 12th October, an estimated 400,000 people, mostly in the South West, have been affected by possibly inaccurate PCR results – perhaps 43,000 people have been falsely told they were negative, and to stop isolating, when they were likely infected. This will include very nearly all of those who tested positive on a Lateral Flow Device. The issues with PCR testing should now have been resolved – some people (tested between 3rd and 12th October) are being asked to isolate and take another PCR.
We are updating this page as we get better information – this is clearly now a national media story. We have kept older information in the page below as a record.

If you’ve got a positive LFT and are either ill or have been in contact with other people who have tested positive (inc. on LFT), it’s likely it is Covid. It’s good to stay home and avoid passing on other illness, even if what you have isn’t Covid-19! If a school or other setting is telling you to attend but you don’t think it makes sense (ie, if you’ve had a negative PCR but have symptoms or are a contact of a case and have a positive LFT), contact the Glos County Council team via (two examples of updated local secondary school advice below)

We’ve had a number of queries about confusing test results and guidance from people in our facebook group. James Beecher has been emailing relevant organisations, here’s a summary of what we’ve been told/have learned from national media coverage (as of 15th October). This page also includes details of how to get tests, and how to look after yourself / when to contact GP / go to A&E if you suspect you have coronavirus, and information on available support (scroll to the bottom).

Uk Health Security Agency statement, 15th October

This statement reveals the problem was with processing of PCR results. While sites in Stroud and Gloucestershire which sent PCR samples to the lab in question have not been confirmed, we believe Stratford Park and potentially other local testing sites must have been affected. While this explains people who did not receive confirmation of their Lateral Flow positive – it also affects people who only got a PCR (those who had hospital tests, and it seems postal tests, do not seem to have been affected – as far as we know so far).

“NHS Test and Trace (NHS TT) have 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).

While investigations are underway into the precise cause, NHS TT estimate that around 400,000 samples have been processed through the lab, the vast majority of which will have been negative results, but an estimated 43,000 people may have been given incorrect negative PCR test results between 8 September and 12 October, mostly in the South West of England.

This is an isolated incident attributed to one laboratory but all samples are now being redirected to other laboratories. 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.

NHS TT is contacting the people that could still be infectious to advise them to take another test. Close contacts who are symptomatic will also be advised to take a test in line with normal practice.  Anyone with COVID-19 symptoms should book a PCR test. Those with a positive LFD test should get a follow up PCR test to confirm they have COVID-19.”

Read the full statement from UKHSA

14th October: West Berkshire Council reveal Department of Health and Social Care have confirmed issues with inaccurate PCR results at a number of testing sites nationally

We do not yet know if/which sites in Gloucestershire have been affected, but it seems like the most plausible explanation for the issues people have had with inconsistent results locally. It underlines the importance of trusting Lateral Flow results at the moment – particularly if you have symptoms, household members have also tested positive or you have been identified as a contact of someone who has tested positive.

“Over the past month, some PCR tests completed at the Newbury Showground testing site, operated by the Department for Health and Social Care (DHSC), have had results sent out that may have incorrectly shown as negative for Covid-19

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.

If you took a PCR test between 3rd – 12th October which was negative, we strongly recommend a retest for you and for any close contacts. It is important to take a PCR test as without it; we cannot complete contact tracing and offer support to the people who need it.”

Read the full West Berkshire County Council statement

The UK Health Security Agency said on 14th October

“UK Health Security Agency (UKHSA) have been made aware of some areas reporting positive LFD test results with subsequent negative PCR tests and are currently looking into the cause. Whilst the UKHSA investigation is under-way, we advise that if a pupil or staff member has been in close contact with a positive case (such as a household member) or has displayed Covid-19 symptoms and has tested positive on an LFD (but subsequently tested negative on a PCR), they are treated as potentially infectious. We recommend they isolate and remain out of the setting, for 10 days.”

(this wasquoted in a local secondary school’s letter to parents)

Alan McNally, a professor of microbial evolutionary genomics at the University of Birmingham, said on 12th October

“There needs to be really clear and immediate messaging from government around which test [people should] act on. My very clear advice would be that if you have a respiratory infection, stay at home because [otherwise] you’re going to pass it on.”

“But if you’ve got symptoms of a respiratory infection and a lateral flow test that’s positive, I would be working on the assumption that it’s Covid-19 regardless of the PCR result at the moment. That message needs to be made clear, which then buys time for the Department of Health and UKHSA to do a quality audit of the PCR testing process and try to find out where the issue may be.”

Quoted in The Guardian article: “Calls for inquiry as negative Covid PCR tests after positive lateral flow reported

Headteacher at Katharine Lady Berkeley’s School in Wotton-under-Edge says:

We advise students to stay away from school if they have symptoms following a positive LFD test and [/even if they have] a negative PCR test… whilst national advice is that a PCR result overrides the LFD, we continue to be concerned about the pattern we are seeing.”

“They should return only once any symptoms have cleared and they have had a negative LFD or PCR test.”

Quoted in Gloucestershire Live article: “Dozens of pupils isolating after positive Covid tests at Gloucestershire school“, 11th October

Glos County Council Health Protection Team said on 7th October:

  • “PCR tests are the gold standard and, in general, the PCR test result should be relied upon. However in some situations we recommend erring on the side of caution if there is good evidence of Covid-19 infection, for example if an individual has a positive LFD result, has symptoms of Covid-19 and has been a close contact of a confirmed case, it would be prudent for that individual to isolate for 10 days from symptom onset even if they received a negative PCR result.”
  • “A number of factors can impact the result of PCR and LFD tests such as how the sample is taken, the accuracy of the test itself and the prevalence of Covid-19 in the community. Concerns over false positives or false negatives have been raised nationally. We have received reassurance that all LFD test kit brands are equally effective. However they do have different instructions for use and it is important to follow the correct ones” (see table below). Click through for instructions on how to do a rapid lateral flow test, and how to do a PCR test (information about getting tests is available below).
  • “A number of respiratory illnesses are present in the community especially with schools and colleges returning and we encourage people to continue to test regularly as one means of identifying Covid-19 infection and help reduce transmission in our communities. If you have symptoms of COVID-19, self-isolate and take a PCR test.”

South West Health Security Agency:

  • Were but are no longer collating details where people have had issues with inconsistent results. Thanks to everyone who provided batch numbers of the tests undertaken, which manufacturer was used, method of use, on site/off site testing and number of test results being challenged. We understand the organisation has enough information to conduct their investigation.
  • Said on 12th October “We have been made aware of some areas across the country anecdotally reporting positive LFD test results with subsequent negative PCR tests. There is currently no evidence that there are any technical issues with LFD or PCR test kits in relation to these reports” [note that this is about kits, but doesn’t rule out issues with processing of PCR samples]
  • Said on the 7th October “We do not have an explanation as yet, but we are collating the data around this issue and escalating it nationally. There are likely to be a number of factors at play and of course we recommend that symptomatic people remain in isolation”
  • Emphasised on 12th October “With one in four positive cases found through lateral flow tests, rapid asymptomatic testing is an important tool to help reduce the spread of COVID-19 and break the chains of transmission. Free lateral flow tests are available for people who do not have symptoms and who may wish to use regular rapid testing to help manage their own risk and risk to others.”

National NHS guidance says:

If you need local support while isolating try our list/map of neighbourhood networks and local groups, or email us at

You may be eligible for financial support if you need to isolate – see the Stroud District Council webpage. The criteria are quite restrictive but “you may be eligible for a discretionary payment if you are on a low income”.

Get a free PCR test if:

  • You have coronavirus symptoms: a high temperature; a new, continuous cough, or you’ve lost your sense of smell or taste or it’s changed (you could also have other symptoms, particularly early in an infection. Here’s a good list of all the symptoms to look out for)
  • you’ve been in contact with someone who’s tested positive
  • you’ve been asked to get a test by a local council or someone from NHS Test and Trace
  • a GP or other health professional has asked you to get a test
  • you’re taking part in a government pilot project
  • you’ve been asked to get a test to confirm a positive result
  • you’ve received an unclear result and were told to get a second test
  • you need to get a test for someone you live with who has symptoms

Click to Book a PCR test at a drive-in / walk-through site near you or get a home test kit delivered.

Click for information on getting Lateral Flow Tests – as of October 4th you need a code from this website to collect these from pharmacies

More information on coronavirus testing in Gloucestershire is available from Gloucestershire County Council.

We’re continuing to communicate with local organisations working on this because we’d like to be able to signpost to a single official piece of advice, and we are aware people are receiving conflicting advice from official sources at present. If you want to message us privately to discuss your experiences or other information you think might help those conversations, please email (We’ll keep personal information confidential and anonymise and reference to experiences)