Diabetes and the HbA1c Test
If you are diabetic, you will probably be very familiar with blood tests by now. Between the at-home finger-prick tests and the blood samples that need to be taken by a healthcare professional, such tests will make up a big part of the monitoring and control of your disease.
For those of you who suspect you may have high blood sugar levels, we’re sorry to say that these tests may become a big part of your life too.
In the management of diabetes mellitus (the full name for diabetes), there are few tests that are as important as the HbA1c test. This measures what is known as glycated haemoglobin, a compound of glucose (or sugar) and the red blood cells that carry oxygen in your blood.
But what is the normal HbA1c level – for both diabetic and non-diabetic people? In this article, we’ll tell you – along with everything else you need to know about this crucial blood test.
What is the HbA1c Test?
The HbA1c test is the test that measures your average blood glucose levels (or average blood sugar levels). Where the at-home finger-prick test for people with diabetes can tell you your glucose levels in that specific moment, the HbA1c is able to show your blood glucose control over 2 to 3 months.
For people with diabetes – type 1 diabetes or type 2 – it goes without saying that this test plays an essential part of monitoring and managing your condition. The NHS recommends that you take this test around every 3 to 6 months, so that you can gain visibility on the entire history of your blood glucose levels.
What Does HbA1c Test For?
Taken by a doctor, the HbA1c test measures the amount of glycated haemoglobin in your blood. For this reason, the test is sometimes called Haemoglobin A1c or just A1c. A1c itself is a type of haemoglobin, alongside A1a, A1b, and even A2. However, A1c is the most common.
Haemoglobin – commonly known simply as red blood cells – is the protein in your blood that carries oxygen. When your body is unable to process blood sugar correctly, more of this sugar sticks to your haemoglobin and accumulates in your blood. It’s this compound of haemoglobin and blood sugar that we call glycated haemoglobin.
As a result, then, a HbA1c result that is high means that you have too much blood sugar. And this means that you are at risk of some of the complications associated with diabetes.
Understanding HbA1c Results
Once you have had the test, you should receive your HbA1c results quite quickly. You will receive them through your GP in the majority of cases, who will be able to explain to you what they mean. However, it’s really important that you understand them. It’s your health, after all.
When you get your results, then, you will see that the levels of HbA1c are measured in units called mmol/mol. This refers to the number of millimoles per mole. Maybe you remember moles from your school chemistry classes. It’s a common unit to measure chemicals – and has been used to measure the amount of blood glucose for the last decade.
However, before this, simpler percentages were used. So, you may see both mmol/mol and a percentage when you receive your results.
Regardless, it’s important that you understand your results – and, if you are diabetic, keep track of them. If you are not diabetic but are taking the HbA1c test because you or your doctor reckon you are at risk of type 2 diabetes, then it’s crucial you can recognise what healthy levels are of glycated haemoglobin.
What are the Normal HbA1c Results?
So, what are normal HbA1c levels? And what levels signal that there may be a problem with your blood glucose levels?
According to the American Diabetes Association, levels of HbA1c are categorised as follows:
Normal: below 42 mmol/mol, or below 6%
Prediabetes: 42-47 mmol/mol, or 6.0-6.4%
Diabetes: 48 mmol/mol, or 6.5%.
This means that anyone who does not have diabetes should have HbA1c results below 42 mmol/mol. However, if you have diabetes, 48 mmol/mol is often a good target to aim for in your own blood sugar levels. At the same time, this will be a highly-personalised target, set between the patient and their healthcare professional. If the patient is on medication, be aware that this might vary.
Prediabetes, however, signals that your blood sugar levels are higher than normal, but not yet high enough to be considered diabetes. If you don’t change your habits, though, you may soon reach type 2 diabetes.
What Other Factors Affect HbA1c Results?
No matter who you are – diabetic or non-diabetic – you shouldn’t expect perfectly stable blood sugar levels across every HbA1c test that you take. Rather, these things fluctuate – due to your overall health, changes in lifestyle, stress, depression, and any other medications you might be taking.
Your HbA1c levels shouldn’t be affected by kidney disease. However, a high intake of carbohydrates tends to lower HbA1c, while iron deficiency anemia increases HbA1c levels. Meanwhile, a high blood pressure correlates with risk of high HbA1c – and the higher the HbA1c, the greater chances of a higher severity of Covid-19 (coronavirus).
If you feel that you are affected by any of these conditions – or that they are at all relevant to your position – speak to your doctor about it when you take the test.
Key Takeaways
The HbA1c test is a central part of diabetes management and, ultimately, diabetes care. It helps you and your doctor keep track of your blood glucose levels over time – and shows you if you need to take action.
And what is the normal HbA1c level? If you are non-diabetic, this level should be kept below 42 mmol/mol. However, if you are diabetic, 48 mmol/mol is a good target to keep.
¹NHS- Going for regular check-ups–Type 2 diabetes: https://www.nhs.uk/conditions/type-2-diabetes/going-regular-check-ups/
²American Diabetes Association – Diagnosis: https://www.diabetes.org/a1c/diagnosis
³Medicine Matters – HbA1c valid marker of blood glucose in anemia or CKD: https://diabetes.medicinematters.com/primary-care/nephropathy/hba1c-valid-marker-of-blood-glucose-in-anemia-or-ckd/15959208
⁴Chaitong Churuangsuk, Michael E.J. Lean & Emilie Combet (2020). Lower carbohydrate and higher fat intakes are associated with higher hemoglobin A1c: findings from the UK National Diet and Nutrition Survey 2008–2016: https://link.springer.com/article/10.1007/s00394-019-02122-1
⁵Eugene Merzon, Ilan Green, Miriam Shpigelman, Shlomo Vinker, Itamar Raz, Avivit Golan‐Cohen, Roy Eldor (2020). Haemoglobin A1c is a predictor of COVID‐19 severity in patients with diabetes: https://onlinelibrary.wiley.com/doi/full/10.1002/dmrr.3398
While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.
