All you need to know about HbA1c

Why is HbA1c important?

Studies have shown that keeping your HbA1c in target can help prevent diabetes complications related to eyes, kidneys, nerves and blood vessels. The higher your HbA1c, the more likely you are to develop diabetes complications. If your HbA1c is elevated, even a small decrease can help to reduce your risk of complications.

Doctors use the HbA1c result to inform them if diabetes treatment is effective. It helps to guide decisions about changing treatment if the HbA1c is not in target. For example, an HbA1c higher than the target range may result in making lifestyle changes such as reducing food portions, increasing activity, starting a new medication or increasing the dose of an existing medication.

The HbA1c needs to be interpreted with care. The result should not be interpreted on its own. Home blood glucose monitoring is still important as it allow us to:

observe glucose trends throughout the day and night

understand how food, medications, and physical activity affect blood glucose levels.

Speak to your diabetes healthcare professional about your target blood glucose levels and HbA1c.

How is HbA1c checked?

There are two ways in which HbA1c can be checked by:

• taking blood from your vein and sending it to a laboratory. This result may take a couple of days to receive.
• taking blood from your finger. This check uses a ‘point of care’ machine giving you an instant result. A point of care machine is generally reliable, but laboratory tests are considered the gold standard especially for diagnosis and precise monitoring.

How you get it checked will depend on your local doctor or diabetes centre. There is no need to fast for an HbA1c check and it can be done at any time of day.

How often should HbA1c be checked?

People with diabetes are advised to have their HbA1c checked at least every 6 to 12 months, and more often if needed. Medicare offers a rebate on HbA1c checks, up to four times a year.

People who have blood glucose levels in target and do not inject insulin, may only need to have an HbA1c check 1 to 2 times a year.

HbA1c may be checked up to four times a year if you:

• take insulin
• have started a new medication
• have had medication increased
• have an HbA1c out of target
• have frequent low blood sugar (hypoglycaemia)-to adjust treatment safely.

An HbA1c check should be part of your annual cycle of care.

For women with diabetes during pregnancy, up to six checks a year are covered by Medicare. Women living with type 1 or type 2 diabetes and who are planning pregnancy, are also advised to have their HbA1c checked every 2 to 3 months. Together with home blood glucose monitoring, a target HbA1c before pregnancy can reduce the risk of complications such as miscarriage and birth defects.

How are results interpreted?

You may notice two sets of numbers when you see your HbA1c result. Worldwide, HbA1c is reported in two ways. It used to only be reported in a percentage but is now also reported in mmol/mol. However, most health professionals still like to use the percentage result when speaking with patients.

The table below reflects the two ways HbA1c is reported. For example, an HbA1c of 53 mmol/mol is also reported as 7%.

What level should my HbA1c be?

A general target that is recommended to aim for is less than 53 mmol/mol (7%), but HbA1c targets can vary from person to person depending on your age, overall health and risk of low blood sugar. Speak to your doctor about your individual target.

Is HbA1c accurate?

HbA1c has proven to be a very useful tool to judge how well your diabetes is being managed and to guide treatment decisions.

Results may be less accurate in people with anaemia or recent blood loss, kidney or liver disease, pregnancy and some other conditions.

It is important to note that HBA1c does not replace daily blood sugar checks. Your daily reading gives more detail about highs and lows.

Discuss your HbA1c with your diabetes health care professional at your next visit.