Understanding the new HbA1c units for the diagnosis of Type 2 diabetes

N Z Med J. 2012 Sep 21;125(1362):70-80.


In New Zealand laboratories the measurement of glycated haemoglobin (HbA1c) for diagnosis of diabetes is now only reported in SI units of mmol/mol. HbA1c is now recommended as the preferred test to diagnose diabetes in most circumstances. The requirement for a second positive test in asymptomatic individuals is retained. An HbA1c greater than and equal to 50 mmol/mol (repeated on a second occasion in asymptomatic patients) is diagnostic of diabetes and a value less than and equal to 40 mmol/mol represents normal glucose tolerance. For patients with an initial HbA1c result of 41-49 mmol/mol, cardiovascular risk assessment and lifestyle interventions are recommended with repeat HbA1c screening in 6-12 months. For patients whose HbA1c is less than and equal to 40 mmol/mol, repeat screening (including for CVD risk) at intermittent intervals is recommended as per published guidelines.

MeSH terms

  • Blood Glucose / analysis*
  • Coronary Disease / prevention & control
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / analysis*
  • Humans
  • International System of Units
  • Life Style
  • New Zealand
  • Patient Compliance
  • Practice Guidelines as Topic*
  • Reference Standards
  • Risk Assessment / statistics & numerical data


  • Blood Glucose
  • Glycated Hemoglobin A