British health officials say 43,000 people in southwest England may have been wrongly told they don't have the coronavirus because of problems at a private laboratory.
The UK Health Security Agency says a lab in Wolverhampton, central England has been suspended from processing the swabs after reports of false negatives.
The faulty results are among tests processed at the Immensa Health Clinic Lab between early September and this week, reports AP.
The issue was uncovered after some people who were positive for COVID-19 when they took rapid tests went on to show up as negative on more accurate PCR tests.
One local authority, West Berkshire Council, has told people who were tested at the government-run Newbury Showground site between Oct 3 and 12 and were told they were negative to get tested again.
Britain conducts about 1.0 million coronavirus tests a day and reported almost 40,000 new infections a day over the past week.