A blood test result that says HbA1c: 48 mmol/mol can look like a code if nobody has explained it. The good news is that learning how to check HbA1c results is usually straightforward. Find the number, check the unit, compare it with the reference range on your report, then discuss what it means for you with a GP or diabetes team.
HbA1c is useful because it shows your average blood glucose level over roughly the last two to three months. It is not a snapshot of what you ate yesterday, and it does not replace day-to-day glucose checks where these have been recommended. It is one piece of a wider health picture.
How to check HbA1c results on a test report
Start by looking for one of these labels: HbA1c, glycated haemoglobin, or sometimes A1c. Your result may appear in a GP app, an online patient record, a letter, or a printed laboratory report.
Most UK laboratories report HbA1c in mmol/mol. Some websites, older reports, and information from other countries may show a percentage instead. A report may show both, but do not assume the numbers mean the same thing. For example, 48 mmol/mol is approximately 6.5%, not 48%.
Next, check the laboratory reference range printed beside the result. That range matters because reports can be formatted differently. If your result is marked high, low, abnormal, or outside range, it tells you that a clinician should interpret it in context. It does not, by itself, confirm a diagnosis or tell you to change medication.
Also check the test date. HbA1c reflects a longer period than a finger-prick glucose reading, so it is best compared with previous HbA1c results taken weeks or months apart. A single number is helpful. A trend is usually more useful.
HbA1c ranges commonly used in the UK
For adults who are not already diagnosed with diabetes, these ranges are commonly used as a guide:
| HbA1c result | Approximate percentage | What it may indicate | |—|—:|—| | Below 42 mmol/mol | Below 6.0% | Usually within the non-diabetes range | | 42 to 47 mmol/mol | 6.0% to 6.4% | Higher risk of developing type 2 diabetes | | 48 mmol/mol or above | 6.5% or above | May indicate diabetes and needs clinical assessment | | A result below or above an individual target | Varies | For people with diabetes, treatment may need review |
A result of 48 mmol/mol or above is often used as the threshold for diagnosing diabetes. However, a GP may repeat the test before confirming this, especially if you have no symptoms. If you have symptoms of high blood glucose, such as unusual thirst, frequent urination, unexplained weight loss, tiredness, or blurred vision, contact a healthcare professional promptly rather than relying only on an online result check.
What your HbA1c target may be
There is no single perfect HbA1c number for everyone with diabetes. Your target depends on the type of diabetes, your medication, your age, your general health, pregnancy plans, and your risk of hypos – episodes where blood glucose falls too low.
Many adults with type 2 diabetes are given a target around 48 mmol/mol if they manage their condition through lifestyle changes or medicines that do not commonly cause hypos. A target around 53 mmol/mol may be used for people taking medicines that can cause hypos, including insulin or certain tablets. These are common examples, not personal medical instructions.
A lower HbA1c is not automatically better if it comes with frequent hypos, dizziness, falls, or difficulty managing daily life. Conversely, a result above target is not a reason for blame. It is a useful signal to look at food, activity, illness, stress, medication routines, and support options with your care team.
Understand mmol/mol and percentage results
If one result is shown in mmol/mol and another in percentage form, comparing them directly can be confusing. Use an HbA1c conversion calculator for a quick estimate, or ask your pharmacist, practice nurse, or GP surgery to explain the numbers.
As a rough guide, 42 mmol/mol is about 6.0%, 48 mmol/mol is about 6.5%, 53 mmol/mol is about 7.0%, and 58 mmol/mol is about 7.5%. The conversion is not a simple multiplication, so avoid trying to work it out in your head.
Do not confuse HbA1c percentage with a blood glucose reading in mmol/L. Blood glucose meters and continuous glucose monitors may show readings such as 5.5 mmol/L or 10 mmol/L. Those numbers describe glucose at a particular time. HbA1c is a separate laboratory measurement that reflects an average over time.
When an HbA1c result can be less reliable
HbA1c works well for many people, but it is not perfect in every situation. The test measures how much glucose has attached to haemoglobin in red blood cells. Anything that affects red blood cells or haemoglobin can affect the result.
Results can be harder to interpret during pregnancy, after significant blood loss or a blood transfusion, and with some forms of anaemia, kidney disease, liver disease, or blood disorders such as sickle cell disease. Some medicines and recent serious illness can also influence blood glucose or the interpretation of a result.
If your HbA1c result does not match how you feel, your home glucose readings, or a previous pattern, mention this to your clinician. They may use another test or check for an underlying reason. Never adjust insulin, diabetes tablets, or prescribed treatment solely because of one HbA1c figure.
A quick way to review your result before your appointment
Before speaking with a clinician, write down the result, the unit, and the test date. If you have previous results, place them in date order. This makes it easier to see whether the number is improving, stable, or rising.
It can also help to note any changes since your last test. For example, you may have started or stopped medication, been unwell, changed your eating pattern, had a more active or less active period, or experienced ongoing stress. These details give the number practical context.
For people who monitor glucose at home, bring a short record of readings rather than isolated highs or lows. Include the time of day and whether readings were before or after meals where possible. This can help explain why an HbA1c has changed and whether a treatment plan is working safely.
Common questions about checking HbA1c
Can I check HbA1c at home?
Home sampling kits are available, but the quality and follow-up can vary. A GP or NHS diabetes service can advise which testing route is suitable for you. A home result should not replace urgent medical advice, diagnosis, or regular monitoring arranged by your care team.
How often should HbA1c be checked?
It depends on your circumstances. People with diabetes may have it checked every three to six months when treatment is changing or control is not at target, and less often when results are stable. If you are at higher risk of type 2 diabetes, your GP may recommend repeat testing at an interval that suits your risk factors.
Does a high result mean I ate too much sugar?
Not necessarily. HbA1c is influenced by overall blood glucose over time, not one meal or one dessert. Genetics, insulin resistance, medication, sleep, illness, activity, and other factors can all play a part. Focus on workable next steps rather than trying to assign fault to one food.
A clear HbA1c result gives you a starting point, not a verdict. Check the unit, keep the date and previous results handy, and use a GP or diabetes review to turn the number into a plan that fits your health and everyday routine.