Understanding Your HbA1c Level: What Do Your Results Mean?
In short
In the UK, an HbA1c below 42 mmol/mol is normal, 42 to 47 mmol/mol is pre-Diabetes, and 48 mmol/mol or above can mean Type 2 Diabetes. HbA1c is a blood test that shows your average blood sugar over the past 2 to 3 months.
Do you know what your HbA1c level means? Whether you want to understand your latest blood test or learn more about Diabetes, knowing your HbA1c results can help you take better care of your health.
What is HbA1c?
HbA1c (glycated haemoglobin) is a blood test that measures your average blood glucose (sugar) level over approximately the past 2 to 3 months.
When glucose enters your bloodstream, some attaches to haemoglobin, a protein in your red blood cells. The HbA1c test measures how much glucose is attached to this protein, giving healthcare professionals an indication of your longer-term blood sugar levels.
In the UK, HbA1c is reported in mmol/mol. Some American websites use a percentage instead: 42 mmol/mol is 6.0%, 48 mmol/mol is 6.5% and 53 mmol/mol is 7.0%.
What is a normal HbA1c level?
For adults in the UK, an HbA1c below 42 mmol/mol is in the normal range (NICE (opens in a new tab)).
| HbA1c result | What it usually means |
|---|---|
| Below 42 mmol/mol (below 6.0%) | Normal range |
| 42 to 47 mmol/mol (6.0% to 6.4%) | Pre-Diabetes: an increased risk of developing Type 2 Diabetes |
| 48 mmol/mol or above (6.5% or above) | The threshold for Type 2 Diabetes |
A result of 48 mmol/mol or above may require confirmation with another test if you do not have typical symptoms. Your GP will interpret your result alongside your symptoms and medical history.
If your result is in the pre-Diabetes range, read what an HbA1c of 42 to 47 means for you.
What HbA1c target should you aim for with Diabetes?
Most adults with Type 2 Diabetes are given an HbA1c target of 48 mmol/mol (6.5%). If you take a medicine that can cause hypos, the target is usually 53 mmol/mol (7.0%) (NICE (opens in a new tab)).
- 48 mmol/mol: if your Diabetes is managed by diet and lifestyle, or by a medicine that does not cause hypos
- 53 mmol/mol: if you take a medicine linked to hypos, such as a sulphonylurea or Insulin
If you already have Diabetes, your personal HbA1c target may differ from the ranges used to diagnose Diabetes.
Your Diabetes team may set a different target for you, for example if you are older or at risk of falls.
Why is your HbA1c level important?
Your HbA1c matters because persistently high blood glucose can increase the risk of complications affecting your:
- heart
- eyes
- kidneys
- nerves
Diabetes UK puts it plainly: “Even a slightly raised HbA1c level makes you more at risk of serious complications” (Diabetes UK (opens in a new tab)).
Monitoring your HbA1c can help identify an increased risk of Type 2 Diabetes and assess how well your blood sugar is being managed if you already have Diabetes. Understanding your results can help you and your healthcare team decide whether changes to your lifestyle or treatment may be beneficial.
Raised blood sugar is common. Diabetes UK estimates that over 4.7 million people in the UK have a Diabetes diagnosis. Another 6.9 million have blood sugar high enough to put them at increased risk of Type 2 Diabetes (Diabetes UK (opens in a new tab)).
How can you improve your HbA1c level?
Eating well, staying active, sleeping well and following your treatment plan can all help bring a high HbA1c down:
- Eat a balanced diet. Include vegetables, whole grains, beans, pulses and suitable sources of protein. Limit sugary drinks and pay attention to portion sizes.
- Stay active. Regular activities such as walking, cycling or swimming can help your body use insulin more effectively.
- Get enough sleep. Good-quality sleep supports overall health and can influence blood glucose regulation.
- Follow your treatment plan. If you have Diabetes, take prescribed medication as directed and attend regular health checks.
Changes usually take about 3 months to show in your HbA1c, because the test reflects the past 2 to 3 months. If your HbA1c stays high even though you are eating well, there may be other reasons your HbA1c is still high.
For more on food, see which foods help manage blood sugar. If you have pre-Diabetes, these changes can often bring your HbA1c back into the normal range: see can pre-Diabetes be reversed?
How often should you check your HbA1c?
Most people with Diabetes have their HbA1c checked every 3 to 6 months, and you are entitled to the test at least once a year (Diabetes UK (opens in a new tab)).
People at increased risk may need regular monitoring: if you have pre-Diabetes, NICE recommends a blood test at least once a year (NICE (opens in a new tab)).
A standard HbA1c test usually does not require fasting.
What should you do about your HbA1c result?
Talk your result through with your GP or Diabetes healthcare team, then use it to guide your next steps.
Your HbA1c level is more than just a number. It provides valuable insight into your average blood sugar levels and can help you make informed decisions about your health. By understanding your results, maintaining healthy habits and seeking appropriate medical advice, you can take positive steps towards managing your blood glucose.
If you would like help with what to eat to bring your HbA1c down, see my support for pre-Diabetes and Type 2 Diabetes, or read what happens at a Dietitian appointment.
Questions people ask about HbA1c
Is an HbA1c of 42 pre-Diabetes?
Yes. In the UK, 42 mmol/mol is the start of the pre-Diabetes range, which runs from 42 to 47 mmol/mol. It means a higher risk of Type 2 Diabetes, not a diagnosis, and it is a good time to make changes.
Do you need to fast for an HbA1c test?
No. A standard HbA1c test usually does not require fasting, because it reflects your blood sugar over the past 2 to 3 months rather than on the day.
Is a normal HbA1c different for older people?
No. The UK ranges for normal, pre-Diabetes and Diabetes are the same for every adult. If you already have Diabetes, though, NICE says your target can be relaxed if you are older or frailer, for example if a hypo could cause a fall.
Can an HbA1c result be wrong?
Occasionally. Conditions that affect your red blood cells, such as some types of anaemia, sickle cell anaemia and thalassaemia, can make HbA1c less accurate. My post on why your HbA1c may still be high explains more.
