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Everything you need to know about HbA1c

Haemoglobin, A1c, HbA1c, A1c… You’ve probably heard these letters and numbers before. But what do they actually mean? What is a HbA1c test? What is a “normal” HbA1c level? What can you do to lower your A1c? These are great questions. Well, we’ve put together everything you need to know about HbA1c here.

What is the HbA1c test?

Haemoglobin is the part of your blood that carries oxygen. It’s what gives your blood its red colour. When glucose is processed by your body and enters your bloodstream, a small amount of it attaches to this haemoglobin. It binds to produce glycated haemoglobin (commonly known as HbA1c). When your body has trouble using glucose effectively, the amount in your body increases. The result is more glucose gets attached to your haemoglobin.

Red blood cells are regularly replaced in the bloodstream. They only have a lifespan of between 90 and 120 days. This is why an HbA1c measurement only gives an average over the last 2-3 months.

What is a “normal” HbA1c range?

The recommended A1c target for a person living with diabetes is 7% or lower. Some people remember this figure as “lucky number 7". People with diabetes will have their own target HbA1c, as discussed with their healthcare professional.

Guidelines from the National Institute for Health and Care Excellence (NICE) say the ideal HbA1c is 48 mmol/L (6.5%) or lower. However, people who are at risk of developing diabetes will generally have a lower target. It is often 42 mmol/L (6%) or below. In someone without diabetes, a high HbA1c could indicate they have developed diabetes.

Reducing your A1c value can decrease your risk of many diabetes-related complications. Your A1c number gives you and your doctor an idea of how your diabetes is being managed over time. However, it does not tell you about major changes in your day-to-day blood glucose levels during that period.

Why measure HbA1c?

Why is HbA1c important? Well, HbA1c estimates your average blood glucose over a period of time. The higher your HbA1c level is, the more glucose in your blood over that 3 months. This can increase the risk of developing diabetes-related complications such as eye, foot, and kidney problems.

NICE (The National Institute for Health and Care Excellence) recommends nine annual health checks for people with diabetes. Among these nine health checks is HbA1c. Generally, you should test your A1c no fewer than twice a year. Most healthcare professionals suggest testing every three months. That’s because that is the approximate lifespan of blood cells. Speak with your healthcare professional to determine where and how frequently you should test your A1c level. Testing may differ depending on your need.

What is the difference between HbA1c level and a blood glucose level?

There are a few differences between HbA1c and a blood glucose level.

HbA1c level

  • Measured by a healthcare professional in a lab from a blood sample
  • Gives an average of blood glucose levels over the previous 2-3 months
  • Gives a view of longer-term diabetes management and therapy

Blood glucose level

  • Checked at home or on the go via a finger prick test blood glucose monitor
  • Shows a snapshot of what your current blood glucose level is
  • Gives a reading that can be acted on immediately to make day to day adjustments to your insulin or diet as needed

What does my HbA1c level mean?

Knowing your HbA1c level is one matter, but actually understanding what it means is another. Data isn’t useful if you can’t understand it.

HbA1c is an average of blood sugar (blood glucose) levels. A higher or above target HbA1c means that blood sugar levels have been consistently above target. This includes the 2-3 month period before the HbA1c measurement.

That data would suggest that your current therapy plan may not be working for you. Your healthcare professional can look at making adjustments to help you reduce your HbA1c.

You may find it useful to keep a record of your HbA1c levels. You could use a diary or electronic logbook. It can help you see if you can spot any patterns or trends. What’s important, though, is trying to keep your HbA1c level within your target as much as possible.

Why does my HbA1c level change?

Your HbA1c level will vary depending on the amount of glucose in your blood. If your blood glucose levels have been higher in the weeks before the measurement, then your HbA1c level will reflect that. There are some other factors that can impact your blood glucose levels and your HbA1c:

  • Illness for a period of time, for example with the flu
  • Lifestyle changes that have affected your activity level
  • Feeling stressed or are depressed

Some medications, such as steroids, can also impact your HbA1c. Some medical conditions which affect the red blood cells could also impact HbA1c. Please speak to your healthcare professional if this is the case.

How to reduce my HbA1c

It’s essential to try and keep your HbA1c level within your target range. We know this isn’t easy and takes time. But there is evidence to suggest that every 11 mmol/L (1%) HbA1c reduction can make a difference. It can lead to a significant reduction in the risk of diabetes-related complications.

If your HbA1c is above your individual target, there are several things that can bring it down to target

You can:

  • Exercise more regularly
  • Eat a healthy, balanced diet
  • Stop smoking (if you do smoke)
  • Talk to other people with diabetes to learn from their experiences
  • Look into local or online diabetes education courses you could attend or tools you could use. Your healthcare professional may be able to suggest some that would be suitable for you.

Your healthcare professional may also review your medication and make some adjustments.

Is HbA1c the only measure for diabetes management?

Since HbA1c is an average value, it doesn’t generally show day-to-day changes in your blood glucose. For this reason, it is generally used in combination with other things. Another helpful bit of information is your time in range. This looks at how often you are in your target blood sugar range and the amount of time spent too high or too low.

HbA1c is a really important tool for you and your healthcare professional in managing your diabetes. However, It is not the only tool. I can be used in combination with other measures. If you are unsure when your last HbA1c level was taken, please contact your healthcare professional. They can check and see when you should next have one.

References:

Stratton I M et al. Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35). BMJ 2000; 321: 405-412. https://doi.org/10.1136/bmj.321.7258.405

The content is provided for general information only. It is not intended to amount to advice on which you should rely – you must obtain professional or specialist advice before taking, or refraining from, any action on the basis of the content. Although we make reasonable efforts to ensure that the content is up to date, we make no representations, warranties or guarantees, whether express or implied, that the content is accurate, complete or up-to-date.

Sources

https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/hba1c

https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/15-...

https://jdrf.org.uk/information-support/managing-type-1-diabetes-3/what-...

https://rcni.com/hosted-content/rcn/diabetes/managing-diabetes

28 May 2021