The difference between HbA1c and blood glucose monitoring for diabetes

When it comes to your health, it can seem like there’s a never-ending list of things to keep track of.

But if you have diabetes, there are two things you can’t afford to forget or confuse:

• regular blood glucose monitoring and
• the HbA1c blood test.

And while people sometimes think they’re one and the same, these two tests check and report on blood glucose in two completely different ways.

In this article we explain why you need both to monitor diabetes, and how an HbA1c blood test is like a blood sugar ‘batting average’. It’s also used to monitor your risk of developing diabetes.

Blood sugar snapshots and average levels over time

If you have diabetes, you may do blood glucose monitoring with test strips at home several times a day. And if you use insulin, it’s important to get accurate results so you can make better decisions about managing your diabetes.

The HbA1c blood test (also known as A1c, glycohaemoglobin and glycated haemoglobin) is a blood test your doctor may order every few months.

If you’re a cricket fan, you know that how many runs a batsman scores in a day isn’t always a good indicator of how well they’re performing. You need to look at their batting average for the entire season.

In the same way, blood glucose monitoring gives you a snapshot at a particular time, while the HbA1c blood test shows what’s happening over a longer period.

Your blood sugar level changes constantly depending on when you eat, when and how much you exercise or whether you’re stressed.

Blood glucose monitoring is important. It can help you work out your insulin dose and monitor any fluctuation in your blood sugar level. But depending on when you take the test, you may miss the highest or lowest points in each day.

This is where the HbA1c test comes in. Your HbA1c level reflects your average blood sugar level over the previous eight to 12 weeks, which is why your doctor may recommend taking the test every three months or so.

It’s all about how sugar attaches to your red blood cells

Some of the glucose in your blood attaches to your red blood cells. When your blood sugar is high, more glucose attaches to them. And when blood sugar is low, less glucose attaches to them.

The glucose remains attached for the lifespan of each red blood cell (around three months).  That’s why your HbA1c level reflects your average blood sugar over the previous three months.

Getting to know your HbA1c level

Knowing your HbA1c level is important, as there’s a proven link between high HbA1c levels and diabetes-associated problems such as heart disease, stroke, kidney failure, loss of sight, and foot ulcers.

If you have diabetes, your doctor will recommend a HbA1c level based on your particular life stage and circumstances. The closer your HbA1c level is to your recommended level, the less likely you’ll develop diabetes complications. And if any of these complications do develop, it will more likely be later in life.

The HbA1c blood test is also used in Australia to diagnose diabetes as well as pre-diabetes – a condition where blood glucose is higher than normal but not high enough to be classified as having diabetes. According to Diabetes Australia, two million Australians have pre-diabetes, which puts them at high risk of developing type 2 diabetes.

Diabetes NSW & ACT CEO Sturt Eastwood says there’s strong evidence that type 2 diabetes can be prevented if people take action early.

“Strong evidence shows that type 2 diabetes can be prevented in more than half of cases in the high risk (pre-diabetes) population by eating well and exercising.”

Sturt Eastwood, Diabetes NSW & ACT CEO

If you’re worried you might be developing diabetes you can do a type 2 diabetes risk assessment or take an HbA1c blood test and discuss the results with your doctor.

Monitor your blood sugar levels from home

Blood glucose is usually measured with a glucometer, either at home or at your doctor’s surgery.

Modern home glucometers can give highly accurate results and make it easy to get the information you need.

While your doctor can order a blood test for HbA1c (which is done at a pathology collection centre), you can also do a simple HbA1c blood test at home.

This at-home test involves putting a couple of drops of blood on a special collection card (just like a fingerprick test) and posting it back to our Canberra laboratory. In a few days we’ll give you the results through our secure website. You can then share the results with your doctor as you choose. This blood testing service also allows you to track your results over time via our secure website.

If you’d like more information about diabetes testing, visit Diabetes Australia or Diabetes NSW&ACT.

Blogs on related topics:

• How do you know if you have diabetes?
• How accurate is a fingerprick blood test?

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