More than 55,000 people in England will need repeat blood tests after errors in machines used to diagnose type 2 diabetes, a BBC investigation has revealed.
The failures, linked to equipment made by Trinity Biotech, have already led to some patients being wrongly diagnosed and prescribed unnecessary medication.
NHS England has confirmed that 16 hospital trusts were using the machines, which produced inaccurate results in the haemoglobin A1C test – the standard procedure for diagnosing and monitoring type 2 diabetes.
The Medicines and Healthcare products Regulatory Agency (MHRA) first received reports of problems with the devices in April 2024. Trinity Biotech says it is working with regulators and has issued safety notices to hospitals.
One patient, 36-year-old Vicky Davies from Hull, was told in October 2024 that she had type 2 diabetes. She was placed on the maximum daily dose of Metformin after initial lifestyle advice, only to be told months later that her results may not have been accurate.
She described the impact of the ordeal: “It’s had a huge effect on my life. Since the diagnosis I have suffered with stress and had to take time off work to attend appointments. I’ve complained to my GP, but I didn’t really get an apology. I’m just so angry.”
During the four months she took Metformin, Davies suffered dizziness and stomach problems. She has since been advised to stop the medication.
NHS England says the clinical risk to patients is considered low, as lifestyle advice and support programmes are generally offered before medication. Dr Clare Hambling, national clinical director for diabetes, said: “Being potentially misdiagnosed with any long-term condition, such as type 2 diabetes, is understandably worrying, however the clinical risk of harm to patients following this issue is low.”
NHS trusts are now recalling patients for retesting, with GPs and hospitals contacting those affected. Fewer than 10% of NHS laboratories were using the faulty machines, and all affected trusts have either recalibrated equipment or switched to new systems.
In September 2024, it was revealed that 11,000 patients at Luton and Dunstable Hospital required retesting after incorrect results. Since then, NHS England has acknowledged that type 2 diabetes diagnoses increased by 10,000 in 2024 – around 4% higher than expected – raising further concerns about misdiagnosis.
By July 2025, the MHRA confirmed reports that the machines had produced a “positive bias”, meaning some patients were wrongly identified as pre-diabetic or diabetic.
In response to the findings, Trinity Biotech said: “The company has worked closely with the MHRA to resolve the issues experienced by some UK labs using the system.” It added that three Field Safety Notices were issued in 2024 to all UK users, highlighting the potential for positive bias and reminding laboratories of correct operating procedures.
People currently taking diabetes medication are urged to seek medical advice if they experience symptoms such as:
• Hypoglycaemia: shaking, sweating, confusion or loss of consciousness
• Hyperglycaemia: excessive thirst, blurred vision or recurrent infections
The NHS has reassured patients that anyone requiring a repeat test will be contacted directly by their GP or local hospital.
