HbA1c test

What is an HbA1c test?

HbA1c is a blood test that is used to diagnose type 2 diabetes. It is also used to monitor blood glucose control in people with diabetes.

HbA1c is short for glycated haemoglobin. The test is also sometimes called haemoglobin A1c.

Haemoglobin (Hb) is the protein in red blood cells that carries oxygen through your body. HbA1c refers to glucose and haemoglobin joined together (the haemoglobin is ‘glycated’). The amount of HbA1c formed is directly related to the amount of glucose in your blood.

Red blood cells live for an average of 120 days, so HbA1c gives an indication of how much sugar there has been in your blood over the past few months. It’s different to a blood glucose test, which measures how much sugar is in the blood at that moment.

Why would I need an HbA1c test?

If you are at increased risk of type 2 diabetes, your doctor may recommend this test to check if you have diabetes. The HbA1c test may also be done if you have symptoms of type 2 diabetes, to confirm a diagnosis.

For people with diabetes, the test is used to indicate how well your diabetes has been controlled over the last few months. People with diabetes are advised to have this test every 3 months. This can be less frequent if your blood sugar levels are well controlled.

Monitoring HbA1c in people with diabetes is important. That’s because the higher your HbA1c, the greater your risk of developing diabetes complications such as:

• diabetic retinopathy
• diabetic kidney disease
• diabetic neuropathy

How to prepare for an HbA1c test

No preparation is needed for this blood test.

Understanding your results

It’s important to discuss your test results with your doctor to see what they mean in your situation.

Diagnosis of diabetes

A diagnosis of diabetes can be made if your HbA1c result is 6.5% (48 mmol/mol) or more. Sometimes the test needs to be repeated to confirm the result.

If your HbA1c level is lower than this, you might need other tests to check whether you have diabetes or not.

Diabetes monitoring

If you have diabetes, the recommended general HbA1c target is 7% (53 mmol/mol) or less.

Your HbA1c target will depend on several factors, such as:

• the type of diabetes you have
• how long you have had diabetes
• your health in general

If your HbA1c result is higher than your target range, your doctor may consider changing your treatment or monitoring your blood sugars more closely.

What can affect my result?

Some medical conditions can alter HbA1c results, including:

• anaemia
• iron deficiency
• kidney failure
• pregnancy