HbA1c is a blood test that is used to help diagnose and monitor people with diabetes. It is also sometimes called a haemoglobin A1c, glycated haemoglobin or glycosylated haemoglobin.
What is being tested?
HbA1c refers to glucose and haemoglobin joined together (’glycated’). Haemoglobin is the protein in red blood cells that carries oxygen throughout your body. The amount of HbA1c formed is directly related to the amount of glucose in your blood.
Red blood cells live for up to 4 months, so HbA1c gives an indication of how much sugar you’ve had in your blood over the past few months. It’s different to the blood glucose test, which measures how much sugar you have in your blood at that moment.
Why would I need this test?
The test for HbA1c indicates how well your diabetes has been controlled over the last few months. It can also be used to diagnose diabetes.
People with diabetes are advised to have this test every 3-6 months, or more frequently if it is not under control.
How to prepare for this test
No preparation is needed for this test.
Understanding your results
If you have not previously been diagnosed as having diabetes, an HbA1c of 6.5% or more can indicate that you do have diabetes. If your level is lower than this, you might need other tests to check whether you have diabetes or not.
If you do have diabetes, your doctor will usually aim for an HbA1c of 6.5-7%. If the HbA1c is higher than the target range, your doctor may consider changing your treatment or closer monitoring.
There are some medical conditions, such as anaemia, that change red blood cells and affect your HbA1c result.
You should discuss the results with your doctor to see what they mean in your particular situation.
About HbA1c testing
Visit Lab Tests Online website for more information about HbA1c testing.
About blood testing
Visit our ‘Guide to blood testing’ to learn more about blood tests in general with information such as:
- what to consider before having the test
- what happens during a blood test
- results accuracy
- blood tests cost.
Last reviewed: September 2016