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The following guidance is provided for the diagnosis of diabetes:

Normal - Fasting plasma glucose (FPG) <6 mmol/l. HbA1c <42 mmol/mol. 2-h PG <7.8 mmol/l

  • Categories of increased risk for diabetes
  • Impaired fasting glucose (IFG) - FPG ≥ 6 to 6.9 mmol/l) 
  • Impaired glucose tolerance (IGT) - 2-h PG (75 g OGTT)
  • A1C - 42-47 mmol/mol (6.0 to 6.4%)

Diabetes mellitus - A1C ≥ 48 mmol/mol (6.5%), FPG 7.0 mmol/l, 2-h PG >11.1 mmol/l; randomPG >11.1 mmol/l

In the absence of unequivocal symptomatic hyperglycaemia, the diagnosis of diabetes must be confirmed on a subsequent day (no delay) by repeat measurement, repeating the same test for confirmation. If two tests don't agree then repeat the one that suggests diabetes. 

NB: Please click on the ppt presentation to view situations when HbA1c is not reliable for diagnosis and for guidance on diabetes risk identification. 

Diagnosing diabetes