A1C Testing
Blood sugar testing is an important part of diabetes management but it’s not the only kind of testing you should be doing. An A1C test, which measures your hemoglobin levels, can tell you your average blood sugar level over the last 2 to 3 months. This is a helpful tool for managing your diabetes but is not a substitute for regular testing.
Learn more about:
What is hemoglobin?
Hemoglobin is a protein inside your red blood cells. It is the part of the red blood cell that carries oxygen from your lungs to the rest of your body. Hemoglobin also carries sugar, because sugars can stick to all kinds of proteins in your body. Once sugar sticks to hemoglobin, it is stuck there for the life of the red blood cell, about 3 or 4 months. The more sugar there is in your blood, the more will end up stuck to the hemoglobin.
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What does the A1C measure?
A1C is a measure of how much sugar is stuck to your hemoglobin. Your A1C reading tells you and your healthcare team what your average blood sugar level has been over the last 2 or 3 months. If you have lots of sugar in your blood and your average blood sugar has been high for the past few months, then your A1C will be high. The A1C test allows you to see how good your overall control has really been. You should talk to your healthcare team about your daily blood sugar tests AND your A1C results.
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How does my A1C reading compare to my daily blood sugar levels?
This chart is an example of how blood sugar compares to A1C. The numbers in this chart are for non-pregnant adults. "Take action" depends on your own plan, and your action steps should be discussed with your healthcare team. Some labs use different ways to test and a have different normal range. Talk to your healthcare team about your results.
 |
A1C Reading |
|
Average Blood Sugar Level |
|
Your Blood Sugar Control |
|
|
14% |
|
360 mg/dL |
|
Very poor control, take immediate action to lower |
|
|
|
10% |
|
250 mg/dL |
|
Poor control, take action to lower |
|
|
|
9% |
|
210 mg/dL |
|
Poor control, take action to lower |
|
|
|
8% |
|
180 mg/dL |
|
Marginal control, take action to lower |
|
|
|
7% |
|
150 mg/dL |
|
Marginal, take action to lower |
|
|
|
6.5%* |
|
135 mg/dL |
|
Good control - target |
|
|
|
6% |
|
120 mg/dL |
|
Very good control |
|
|
*ACE/AACE A1C Target for Glycemic Control.
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How can A1C testing help me?
According to the ACE/AACE guidelines on A1C, higher than 6.5% is a warning sign that your diabetes is out of control. If your hemoglobin A1C is high, your healthcare team may change your diabetes plan to help control your blood sugar better. Changes in your plan are expected from time-to-time and will help bring your A1C closer to normal. When your A1C is close to normal, you know you are doing all you can to stay healthy.
Research shows that good blood sugar control may lower your risk of major health problems including:
- heart disease
- stroke
- kidney disease
- eye disease
- nerve damage
- amputations
- circulation problems
By keeping your blood sugar close to normal, you will stop or delay the damage high blood sugar does to blood vessels and nerves. You can prevent the complications of diabetes.
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Where do I go for an A1C test?
Some doctors can do an A1C in their office by taking a blood drop from a finger stick. You can wait for the results and talk about them right away. The doctor may also send a blood sample to the lab for this test.
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How often should I have an A1C test?
The ACE and AACE recommended that anyone with diabetes should have an A1C done every 6 months for people at or below the target of 6.5%, and every 3 months for those above 6.5% or changing therapy. If you inject insulin, you should have this test done every 3 months. Two major studies have shown the importance of good blood sugar control and the relationship of the A1C to diabetes complications. The first was the Diabetes Control and Complications Trial (DCCT).
In this study, patients with type 1 diabetes had an A1C every month. This gave the healthcare team useful information to change treatment plans. In this study patients who had close to normal A1C were in better health and had fewer cases of eye disease, kidney disease and nerve damage.
The other study was called the United Kingdom Prospective Diabetes Study (UKPDS). This was a study done with patients with type 2 diabetes. People who had good blood sugar control were in better health in this study, too.
Both of these studies show that the hard work it takes to control your blood sugar is worth it. Your healthcare team will help you take good care of your blood sugar. They will tell you how often you should have an A1C.
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