HbA1c Test

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Also known as: Haemoglobin A1c; Glycated haemoglobin
Related tests: Glucose, Microalbumin

At a Glance

Why Get Tested?

To monitor a person’s diabetes and to help treatment decisions. It can also be used to diagnose type 2 diabetes.

When to Get Tested?

When first diagnosed with diabetes and then at least twice a year

Sample Required?

A blood sample taken from a vein in the arm

Test Preparation Needed?


The Test Sample

What is being tested?

Some of the glucose in your blood binds to haemoglobin (the protein that carries oxygen in your red blood cells). This combination of glucose and haemoglobin is called haemoglobin A1c (HbA1c). The amount of HbA1c formed is directly related to the average concentration of glucose in your bloodstream. Red blood cells live for 2–3 months, and because of this, the amount of HbA1c in your blood reflects the average level of glucose in your blood during the last 2-3 months. If your diabetes is not well controlled, your blood glucose levels will be high, causing higher HbA1c levels.

How is the sample collected for testing?

Your blood may be taken from a vein in your arm or, in some cases, a drop of blood from a finger-prick may be used.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

Ask a Laboratory Scientist

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.