New research published this week could help to diagnose as many as 600,000 people nationwide who either have or are at risk from type 2 diabetes.
Type 2 diabetes is most common in adults aged over 40, and takes effect gradually over a prolonged period of time, meaning that symptoms can develop without the affected person being fully aware.
New software, detailed in the British Journal of General Practice, identified large numbers of blood tests where "borderline" cases of high blood glucose levels had not been followed up.
Moreover, of 3.6 million anonymous records, the software found 3,700 cases where diabetes had almost certainly gone undiagnosed, Diabetes.org reports.
The software was developed by Dr Tim Holt from the University of Warwick.
Commenting on the research, Diabetes UK chief executive Douglas Smallwood said: "Diabetes UK has been calling for many years for active programmes to identify people with undiagnosed Type 2 diabetes.
"If rolled out nationally, this research could potentially identify over half a million people who are undiagnosed or at increased risk of developing the condition."
Please click here for advice to help you find the right type of care.