HbA1c Test
A blood test that reflects average blood glucose levels over approximately the previous 2 to 3 months.
What the test involves
HbA1c measures the percentage of haemoglobin in red blood cells that has glucose attached to it. Because red blood cells remain in circulation for several weeks, HbA1c provides an estimate of longer-term blood glucose control.
Why it may be requested
HbA1c may be requested to:
- Help diagnose diabetes
- Identify prediabetes
- Monitor blood glucose control in people with diabetes
- Assess response to diabetes treatment
- Monitor longer-term glucose trends
How to prepare
HbA1c generally does not require fasting. Take your usual medicines unless your healthcare provider gives different instructions.
Tell the healthcare provider about conditions or treatments that may affect red blood cells or haemoglobin because these can sometimes affect the interpretation of HbA1c.
Understanding results
Commonly used ranges are:
- Below 5.7%: generally considered normal
- 5.7% to 6.4%: generally consistent with prediabetes
- 6.5% or higher: consistent with diabetes when appropriately confirmed and interpreted in clinical context HbA1c should not be interpreted in isolation. Symptoms, previous results and other glucose measurements may also be considered.
A test result on its own cannot establish a diagnosis.
