HbA1c
At a Glance
Why Get Tested?
To monitor a person’s diabetes and to aid in treatment decisions
When to Get Tested?
When first diagnosed with diabetes and every 3-6 months
Sample Required?
A blood sample drawn from a vein in the arm or from a fingerstick
Test Preparation Needed?
None
The Test Sample
What is being tested?
As glucose circulates in your blood, some of it spontaneously binds to haemoglobin (the protein that carries oxygen in your red blood cells). This combination is called haemoglobin 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 few months.
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.
The Test
How is it used?
The test for HbA1c indicates how well you have controlled your diabetes 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.
When is it requested?
Diabetes Australia recommends that for all individuals with diabetes 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.
What does the test result mean?
If you have diabetes and your HbA1c is below the target of 7% (also reported as 53 mmol/mol) it is likely that your diabetes is in good control. If your HbA1c rises above 7% (53 mmol/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.
Is there anything else I should know?
If you have an abnormal type of haemoglobin, for example if you suffer from sickle cell disease, accurate results will depend on the method used to measure your HbA1c. If you suffer from a condition causing excess breakdown of red blood cells (haemolysis) or heavy bleeding, your test results may be falsely low. Pregnancy can also affect the test result. Finally, if you are iron deficient or have recently been treated for iron deficiency, this may affect your HbA1c measurement.
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Article Sources
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