What is HbA1c and how is it used to measure diabetes?^206,210

Two people look at glucose data on smartphone; one seated with a towel around neck and wearing a continuous glucose monitor

A HbA1c or A1c test is used by doctors and healthcare professionals to measure your average blood sugar level over the last 2-3 months. The test result is used to diagnose, monitor, and manage treatment decisions for diabetes. HbA1c is measured as a percentage(%).

Why is HbA1c important?²¹⁰

In general, a higher HbA1c indicates a higher risk of long-term diabetes complications. If you have either type 1 or type 2 diabetes, your doctor will check your HbA1c levels to decide on the best treatment plan for you, and help you set a target to lower your HbA1c.

What is considered a normal HbA1c range?²¹¹

Non-diabetes

A healthy HbA1c is below 5.7%

Prediabetes

HbA1c between 5.7-6.4% indicates prediabetes. This means you are at risk of developing diabetes

Diabetes

HbA1c of 6.5% or above indicates diabetes

Gestational diabetes

If you do not have diabetes, HbA1c of 5.9% in the first 15 weeks of pregnancy may mean you are at higher risk for gestational diabetes.

HbA1c on its own does not tell the full story

HbA1c does not give a full picture of your blood sugar levels. It does not account for the ups and downs of your blood sugar within a day or show patterns in your blood sugar over time. HbA1c also can't tell you whether you experience hypoglycemia. Gaining insight into what's affecting your blood sugar can help customize a diabetes management plan suited to your individual needs and routine.

Time in Range (TlR) is increasingly being used to assess blood sugar in combination with HbA1c. TIR is a measurement of how much of the day your blood sugar spends within your target range. It is measured as a percentage (%) ²¹¹. The higher the TIR, the better the glucose control.