What Is HbA1c?
HbA1c (glycated haemoglobin) measures the percentage of haemoglobin in your red blood cells that has glucose attached to it. Because red blood cells live for approximately 3 months, HbA1c reflects your average blood sugar level over the past 2–3 months — making it far more informative than a single blood glucose reading.
HbA1c Reference Ranges
- Normal (non-diabetic): Below 5.7%
- Prediabetes: 5.7%–6.4%
- Diabetes: 6.5% and above
- Diabetic target (on treatment): Below 7.0% (general); <8.0% for elderly or high hypoglycaemia risk
Advantages Over Fasting Blood Sugar
- No fasting required
- Not affected by a single day's diet
- Shows average control, not just the moment of testing
- Better predictor of diabetic complications
When Is HbA1c Less Reliable?
- Haemoglobin disorders (sickle cell disease, thalassaemia) — false results
- Severe anaemia or recent blood transfusion
- Haemolytic anaemia — artificially low HbA1c
- Iron deficiency — can falsely elevate HbA1c
What Your HbA1c Result Means
| HbA1c | Estimated Average Glucose | Category |
|---|---|---|
| 5.0% | 5.4 mmol/L (97 mg/dL) | Normal |
| 6.0% | 7.0 mmol/L (126 mg/dL) | Prediabetes |
| 7.0% | 8.6 mmol/L (154 mg/dL) | Diabetes target |
| 9.0% | 11.8 mmol/L (212 mg/dL) | Poor control |
FAQ
How often should I check my HbA1c? If well-controlled (below target): every 6 months. If recently changed medication or poorly controlled: every 3 months. New diabetics: every 3 months until stable.