HbA1c (glycated hemoglobin) shows your average blood sugar over the past 2 to 3 months by measuring how much sugar has attached to hemoglobin in red cells.
- Normal range (adults)
- Below 5.7% (below 39 mmol/mol)
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- Glycated Hemoglobin, A1c, Hemoglobin A1c, Haemoglobin A1c, GHB, Glycosylated Hemoglobin, HBA1C, Hb A1c
HbA1c normal range
| Group | %Conventional units: US, South Asia | mmol/molSI units: UK, Europe, Australia, international |
|---|---|---|
| Adults | Below 5.7 | Below 39 |
5.7–6.4% (39–47 mmol/mol) is prediabetes; 6.5% (48 mmol/mol) or above is diabetes.
Your report may use either unit system; labs in the Gulf often print both. Ranges also vary slightly between laboratories, so the range printed on your own report is the one to go by.
Why is the HbA1c test done?
It is used to diagnose diabetes and prediabetes and is the main test for checking diabetes control. You do not need to fast for it.
What does a high HbA1c level mean?
5.7 to 6.4% (39 to 47 mmol/mol) is prediabetes; 6.5% (48 mmol/mol) or above is diabetes. Most people with diabetes aim for below 7% (53 mmol/mol). Each 1% reduction lowers the risk of eye, kidney and nerve damage.
Common causes
- Type 2 or type 1 diabetes
- Prediabetes and insulin resistance
- Iron deficiency anemia can falsely raise HbA1c
- Kidney disease
Diet and lifestyle tips
- Cut all sugary drinks, sweets and desserts
- Halve your portion of white rice, bread and bakery items; choose whole grains, oats, lentils and beans
- Fill half your plate with non-starchy vegetables
- Eat protein with every meal
- Be active for 150 minutes a week, including walks after meals
- Lose excess weight, even 5% helps
- Take medicines exactly as prescribed
What does a low HbA1c level mean?
A low HbA1c is not a concern in people without diabetes. In people on diabetes medicine, very low values can mean frequent low sugars.
Common causes
- Over-treatment with diabetes medicine
- Recent blood loss or anemia from red-cell breakdown (can falsely lower HbA1c)
- Pregnancy
Diet and lifestyle tips
- Do not cut food further if you are on diabetes medicine; ask your doctor to review your dose
When should you see a doctor?
Talk to your doctor if your HbA1c is 5.7% (39 mmol/mol) or above. People with diabetes usually check it every 3 to 6 months.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.