Thousands of patients were misdiagnosed with diabetes and wrongly put on medication due to NHS blood test mistakes.
At least 55,000 people will need further tests after errors were found in machines used to diagnose the condition.
Up to 10 per cent of NHS laboratories in England are affected by the issues, NHS England said.
The problems mean some patients have been wrongly diagnosed with type 2 diabetes and then unnecessarily prescribed a medication with potentially unpleasant side-effects.
NHS England confirmed that 16 hospital trusts use the machines, made by Trinity Biotech, which have produced inaccurate test results.
