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Diabetes UK supports the diagnostic criteria published by the WHO in 2006: "definition and diagnosis of diabetes mellitus and intermediate hyperglycaemia". Diabetes UK also welcomes the 2011 decision by the WHO to accept the use of HbA1c testing in diagnosing diabetes: "use of glycated haemoglobin in the diagnosis of diabetes mellitus".
Information on the diagnostic criteria for diabetes is below. For further information and an explanation of terms and classifications please refer to the full WHO guidelines.
Methods and criteria for diagnosing diabetes
The criteria for diagnosing gestational diabetes is different. Gestational diabetes should be diagnosed if the woman has either:
Haemoglobin A1c (HbA1c) testing to diagnose diabetes
An HbA1c of 48mmol/mol (6.5%) is recommended as the cut off point for diagnosing diabetes. A value of less than 48mmol/mol (6.5%) does not exclude diabetes diagnosed using glucose tests.
Finger-prick HbA1c should not be used unless the methodology and the healthcare staff and facility using it can demonstrate within the national quality assurance scheme that they match the quality assurance results found in laboratories. Finger prick tests must be confirmed by laboratory venous HbA1c in all patients.
In patients without symptoms of diabetes the laboratory venous HbA1c should be repeated. If the second sample is <48mmol/mol (6.5%) the person should be treated as at high risk of diabetes and the test should be repeated in 6 months or sooner if symptoms develop.
Situations where HbA1c is not appropriate for diagnosis of diabetes:
Patients whose HbA1c is under 48 mmol/mol (6.5%)