Why would I need this test?
The test for HbA1c is used to diagnose and monitor diabetes.
For people who have diabetes, the test is used to indicate how well the diabetes has been controlled over the last few months. People with diabetes are advised to have this test every 3 to 6 months, or more frequently if it is not under control.
This is important. The higher the HbA1c, the greater the risk of developing complications such as problems with your eyes and kidneys.
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 anemia, 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.
When to get tested?
For the diagnosis of type 2 diabetes - only patients at high risk of undiagnosed diabetes should be tested. These are patients with either (i) a medical condition or ethnic background associated with high rates of type 2 diabetes, or (ii) an Australian type 2 diabetes risk (ASTERISK) score of 12 or greater, placing them at increased risk of diabetes – (reimbursed by Medicare).
For monitoring of diabetes - every 3-6 months - 4 times per year if glycemic goals are not met or when therapy plan has changed; at least 2 times a year if meeting treatment goals and under stable glycemic control. Medicare reimburses four monitoring HbA1c tests per year. More frequent monitoring is needed in pregnancy, up to six tests in a 12-month period which is covered by Medicare
Sample required?
A blood sample drawn from a vein in the arm or from a finger stick.
Test preparation needed?
None.
What is being tested?
As glucose circulates in your blood, some of it spontaneously binds to hemoglobin (the protein that carries oxygen to your red blood cells). This combination is called hemoglobin A1c (HbA1c). The amount of HbA1c formed is directly related to the amount of glucose in your blood. If your diabetes is not well controlled, your blood glucose levels are high, causing higher HbA1c levels. HbA1c levels do not change quickly, since red blood cells live for 3-4 months. Because of this, the amount of HbA1c in your blood reflects the average amount of glucose in your blood during the last 2-3 months. The higher the level of glucose in the blood, the more glycated hemoglobin is formed.
How is the sample collected for testing?
Your blood may be drawn from a vein in your arm or, in some cases, a drop of blood from a finger-prick may be used.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
When it is requested?
When your doctor suspects that you might have diabetes. After diabetes has been diagnosed, Diabetes Australia recommends that for all individuals, HbA1c is measured every 3-6 months. HbA1c may be measured more frequently in those who have just been diagnosed with diabetes, in those whose blood glucose remains too high, or when a treatment plan changes.
How is it used?
The test for HbA1c can be used to diagnose diabetes and also indicates how well your diabetes has been controlled over the last few months. Even though you may have some very high or very low blood glucose values, HbA1c will give you a picture of the average amount of glucose in your blood over that time period. The result can help you and your doctor know if the measures you are taking to control your diabetes are working.
What does the test result mean?
Diagnosis of Diabetes - HbA1c ≥6.5% (48 M MOL / MOL)
Treatment targets:
- General target <7% (53 M MOL / MOL) - If you have diabetes and your HbA1c is below the target of 7% (also reported as 53 M MOL / MOL) it is likely that your diabetes is in good control. If your HbA1c rises above 7% (53 M MOL / MOL), you are at increased risk of developing long term complications such as eye disease, kidney disease or nerve damage and probably heart attack and stroke.
- Recurrent severe hypoglycemia or hypoglycemia unawareness ≤ 64 M MOL / MOL, ≤ 8.0%
Prediabetes - 42–47 M MOL / MOL (6.0–6.4%) Even though labeling people with an HbA1c value slightly under 48 M MOL / MOL (6.5%) with prediabetes is not recommended, the levels suggest a higher risk of developing diabetes.
Why are there two results for HbA1c?
HbA1c is now usually reported with two sets of units. These are the % (NGSP) units with one decimal place which have been used for some time and the new System International (SI) units which are M MOL / MOL with no decimal place and introduced into Australia in 2011. The new units relate to a revised international standard for HbA1c which was developed by the International Federation of Clinical Chemistry (IFC) and therefore are sometimes known as IFC units. To convert results in % units to SI units, the following equation may be used: HbA1c (M MOL / MOL) = 10.93 x HbA1c (% units) – 23.5.
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