Why HbA1c testing? What’s it all about?

Monday, 1 April 2019

The HbA1c test (also known as the A1c or glycated haemoglobin test) is a way of looking at your average blood glucose level over a period of time. We explain what it is, where you can get your test done, why it matters, what your level means and what target you should aim for.

How does the HbA1c test work?

Some of the glucose in your blood attaches to a part of your red blood cells. When your blood glucose is high more glucose attaches to the red blood cells, when blood glucose is low less glucose attaches to the red blood cells. This attachment is permanent for the life span of that particular red blood cell. Individual cells usually have a lifespan of about three months. Taking an HbA1c test every three months is recommend because your HbA1c level will reflect your average blood glucose over the previous three months.

I already do regular blood glucose testing at home, why do I need to do an HbA1c test also?

Your blood glucose level is constantly changing; it will vary when you have eaten, during exercise, after exercise, if you are stressed and so on. Checking your blood glucose is important and is used when making day to day decisions such as selecting your insulin dose or if you are worried that your glucose level is getting a bit low (a hypo). Even if you do take your blood glucose level several times a day you may miss the highest and lowest points which is why the HbA1c test is also needed for good health management. To use a cricket analogy – the blood glucose test is like looking at a batsman’s performance on a single day, the HbA1c test is like looking at the batsman’s batting average over a season.

Why does my HbA1c level matter?

There is a proven link between high HbA1c levels and diabetes-related complications such as stroke, heart and kidney disease, loss of eyesight and amputations. The closer your HbA1c level to your recommended level, the less likely you are to develop these complications. Also, if any of these complications do occur they are more likely to come on later in life, rather than sooner.

I live with diabetes, what is a ‘good’ HbA1c level for me?

Your doctor will recommend an HbA1c level based on your particular lifestage and circumstances.  Usually this will be around 7% (53 mmol/mol), although this can vary. If you are not sure of your target HbA1c have a chat with your healthcare team.

Can HbA1c be used to diagnose diabetes?

Yes, the HbA1c test is now used in Australia to diagnose diabetes and pre-diabetes (pre-diabetes is a condition where your blood glucose is higher than normal but not high enough to be classified as diabetes). If you are concerned that you may be developing diabetes you can take an HbA1c test and discuss the results with your doctor.

I looked at my recent HbA1c test results – why is the HbA1c level shown as two different numbers?

The units used to explain your HbA1c level are changing.  Until recently the results were shown only as a percentage.  Australia is introducing the new international units (IFCC units) which are shown as mmol/mol, for example 7.3% = 56 mmol/mol.  So when you get your test results you will see two sets of numbers.  You can use either when discussing your results with your healthcare team.

Where can I get my HbA1c test done?

You have a few options to choose from when you take your HbA1c test. Your doctor can order the test and you can have a blood sample taken from the vein in your arm. The tube of blood will be sent to a lab for analysis, then you can get your results from the doctor.

There are also finger-prick options.  Some clinics will have a small machine called a point-of-care machine. A drop of blood is taken from your fingertip and within about 10 minutes you can get your HbA1c level. There is also a test kit you can purchase from Diabetes NSW where you take a finger prick sample at home, place a couple of spots of blood onto a card and mail this card to the lab. You will get your HbA1c test results delivered online within a few days.  You can take your test results to your doctor or healthcare team to discuss how to best manage your health.

We hope this gives you a little more insight into one of the tests you take regularly. If you have questions about your HbA1c test or any other diabetes-related test, call our Infoline on 1300 136 588.

Me is all about what you need to do for yourself, managing your diabetes and doing what you can.

Join our community of over 45,000 people living with diabetes