British health officials said on Friday that an estimated 43,000 people in England may have got a false-negative COVID-19 test because of problems at a private laboratory.

Iran PressEurope: The UK Health Security Agency said a lab in Wolverhampton, Central England, had been suspended from processing any tests after reports of people receiving false negatives.

The faulty tests came from Immensa Health Clinic Lab between Sept. 8 and Oct. 12, mostly in the South West of England, the statement says. 

Around 400,000 samples were processed through the lab and the issue was uncovered after some of the people tested positive for COVID-19 after receiving a negative PCR test. Around 43,000 people “may have been given incorrect negative PCR test results,” according to the statement. 

While being investigated, the health agency said it is “an isolated incident attributed to one laboratory” and that it is continuing to contact people who may be infected, advising them to get another test.

“We have recently seen a rising number of positive LFD results subsequently testing negative on PCR,” Dr. Will Welfare, public health incident director, UKHSA said in a statement. “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.”

Immensa Health Clinic has analyzed over 2.5 million samples for NHS Test and Trace and the clinics' CEO, Andrea Riposati, said they are “fully collaborating with UKHSA” on the matter. She added that she does not wish “this matter or anything else to tarnish the amazing work done by the UK in this pandemic.”

As of Oct. 14, the UK has a total of 8.3 million positive COVID-19 cases and over 94 million people have been vaccinated.