Scientists are calling for an urgent investigation after dozens of reports of people testing negative using gold-standard Covid PCR tests, despite testing positive on rapid lateral flow tests, and in many cases experiencing Covid-like symptoms.
The UK Health Security Agency (UKHSA) said it had been made aware of people in some areas of the country anecdotally reporting positive lateral flow test results with subsequent negative PCR tests, and that it was looking into the cause.
Scientists told the Guardian that they would like to see more being done to ensure that members of the public who may be infected with the virus are not being falsely reassured that it is safe for them to mix with other people.
Alan McNally, a professor of microbial evolutionary genomics at the University of Birmingham, who helped establish some of the Lighthouse labs, state-funded Covid-19 testing facilities, said: “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 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.”
Anecdotal reports have suggested that the issue may be more widespread in south-west England, prompting speculation that a new variant of Sars-CoV-2 may be the cause. However, GPs in Manchester and Oxfordshire have also reported discrepancies between lateral flow and PCR test results, and scientists think a new variant is unlikely.
Scientists call for an excuse to keep more of themselves in a cushy job?
What a shocker!
As LongDrivers has said, it’s easy to skew the test & get a false positive - which purely as a thought you understand might be just the thing for a family wanting to take their kids with them on a holiday now that’s an option, rather than facing fines from schools for taking your children out of school in term time.
The lateral flow tests have always been known to be up to two thirds inaccurate on people who are positive. And most concerning, the lateral flow tests are most inaccurate on people when they are at their most contagious. That is before the full impact of Covid hits them.
In other parts of the world, people have advised to throw any lateral flow tests away. As they are accepted to be so inaccurate. And I think the system they tried in the North West care homes before Christmas was dropped, as the lateral flow tests were too inaccurate to trust.
A Cochrane review, published on 24 March 2021, investigated whether commercially available, rapid point‐of‐care antigen (lateral flow) and molecular tests were accurate enough to diagnose COVID‐19 infection reliably, and to find out if accuracy differed in people with and without symptoms
They found that in people with confirmed COVID‐19, antigen tests correctly identified COVID‐19 infection in an average of 72% (ranging from 34% to 88%) of people with symptoms, compared with 58% of people without symptoms. In addition, they found that the tests were most accurate when used in the first week after symptoms developed.
Lateral flow tests are in some circumstances no more accurate than reading tea leaves. That is one third correct. Government science & Mystic Meg are equally trustworthy.
There have been a number of cases where people have tested positive using lateral flow tests - but then received a negative PCR result.
Trish Caller 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 returned a negative PCR test result but ended up having covid. She had to be admitted to hospital for the virus and pneumonia. She is now recovering at home in Taunton - but says she has lost faith in the testing system.
Pamela Constable, from Shipham in Somerset, says she has also suffered as a result of the testing system. Pamela felt her negative PCR test result was incorrect. She booked a second PCR test which confirmed she did have the virus. She recently tested positive via multiple lateral flow tests at home but then received a negative PCR result. The nursery worker was surprised by the discrepancy and booked herself a second PCR test before returning to work as a matter of precaution.
She said: “By the Monday morning my symptoms had got worse. I normally don’t work on a Monday, so I didn’t go into the nursery that day. I went for another PCR test and that was then positive.”
She said she could have passed the virus on to other people had she accepted that first negative PCR result: "The normal protocol is if you have a positive lateral flow and then you get a negative PCR you carry on as usual.
The problem has severely impacted schools and education, including Katherine Lady Berkeley’s School in Gloucestershire, where more than 40 students and six staff members have been forced to self-isolate because of coronavirus.
Just under 3% of the school’s population are absent because of the virus – which is below the national average – but precautions are in place because staff and students have had positive lateral flows followed by negative PCR results.
This is all relatively new and I am personally surprised that at this point there is a test and a shot at all. I’m sure they will work the kinks out. Lets just hope no kinks with vaccine as time goes on.
People who got a negative result from a Covid testing site in Berkshire earlier this month are being told to book another test, amid fears they were mistakenly given the all-clear.
Some PCR tests carried out at Newbury Showground resulted in false negatives, West Berkshire Council said.
The BBC has been told the problems relate to one specific lab, rather than the site, and have now been fixed.
But some other people in south-west England are thought to be affected too.
Health officials are set to give out more details later on Friday.
An investigation was launched into reports of people receiving negative PCR test results after they had previously tested positive on a lateral flow device.
NHS Test and Trace estimates that 400,000 coronavirus test samples were processed through the Immensa Health Clinic lab in Wolverhampton - and an estimated 43,000 people may have been given incorrect results between 8 September and 12 October.
The UK Health Security Agency (UKHSA) said most were in the South West of England.
It insisted there are “no technical issues” with the lateral flow or PCR tests, adding that other labs are “working normally” and described it as an “isolated incident attributed to one laboratory”, but said all samples are now being redirected to other labs.
Test and Trace is contacting people that could still be infectious to advise them to take another test, while close contacts who are symptomatic will also be urged to get tested.
So, this is the lab involved in the PCR testing failure.
