Errors at Wolverhampton testing lab led to incorrect reporting of PCR test results

The UK Health Security Agency (UKHSA) has published the findings of its investigation into errors at the Immense laboratory in Wolverhampton.

The laboratory was commissioned to provide additional capacity for NHS Test and Trace from 2 September 2021. Testing was suspended on 12 October 2021 due to reports of inaccurate results.

The cause of the inaccurate results was the incorrect setting of the threshold levels for reporting positive and negative results of PCR samples for coronavirus (COVID-19) by staff. Therefore, some PCR tests were reported by the lab as negative, when they would have been positive if the threshold was correctly set.

Analysing the background infection rate, UKHSA estimate that this could have led to around 39,000 results being incorrectly reported as negative instead as positive. This is the equivalent of around 10 per cent of samples tested at the laboratory between 2 September and 12 October 2021 and 0.3 per cent of all samples tested by NHS Test and Trace during this time.

The serious incident investigation by UKHSA found that no singular action or process implemented by NHS Test and Trace could have prevented the errors within the Immensa laboratory arising. However, a range of ways to enable earlier detection of any similar laboratory errors wherever possible were identified.

Richard Gleave, UKHSA director and lead investigator, said: "Through this investigation we have looked carefully at the arrangements in place for overseeing contracts of private labs providing surge testing during this time. We have concluded that staff errors within Immensa’s Wolverhampton laboratory were the immediate cause of the incorrect reporting of COVID-19 PCR test results in September and October 2021.

"It is our view that there was no single action that NHS Test and Trace could have taken differently to prevent this error arising in the private laboratory. However, our report sets out clear recommendations to both reduce the risk of incidents like this happening again and ensure that concerns are addressed and investigated rapidly."

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