Past Feature Article
Click here for past articles
Knowing Your Numbers - Q&A on A1C
Written By: Stephanie Harriman, PharmD,
Community Practice Resident,
University of Pittsburgh/Rite Aid Corporation
Having diabetes can be overwhelming. You may be told to watch your diet, exercise, take several medications, inject insulin and check your blood sugar several times a day- all in an effort to control your blood sugar. While it may seem at times that this health condition runs your life, you can empower yourself by knowing what your blood sugar goals are and taking an active role in keeping your blood sugar under control.
What is an A1C?
An A1C (also known as glycated hemoglobin or HbA1c) is determined by a blood test and gives you a picture of your average blood sugar over a span of about 3 months. This number gives you an idea of how well your diabetes treatment plan is working for you.
Hemoglobin is a protein in red blood cells that carries oxygen. The average lifespan of a hemoglobin molecule is 120 days. As it flows through your body, it joins with extra sugar/glucose in your blood, forming glycated hemoglobin. As the level of sugar rises in your blood, more of it joins to the hemoglobin molecules. It is possible to measure the percentage of A1C in the blood. By having an A1C test, you can get an idea of your average blood sugar/glucose control for the past few months.
What is a normal A1C?
Generally, a normal A1C for a person without diabetes is considered to be less than 6%. The American Diabetes Association (ADA) recommends that patients with diabetes maintain an A1C of less than 7%, in order to prevent the complications of high blood sugar. Lowering A1C to an average of about 7% has clearly been shown to reduce complications of diabetes. However, it should be noted that less stringent goals may be appropriate for anyone with a history of severe hypoglycemia (low blood sugar), children, or those with additional health conditions. A1C goals should be set for each person individually. It is important to work with your health care provider to determine your specific A1C goal.
How does A1C relate to other blood sugar readings?
The Diabetes Control and Complications Trial (DCCT) is a study that demonstrated how control of glucose levels affected complications. The following chart came out of that study and shows how A1C relates to other blood sugar readings:
Correlation between A1C level and mean
plasma glucose levels on multiple testing
over 2-3 months
| A1C (%) |
A1C (%) |
| |
| mg/dl |
mmol/l |
| 6 |
135 |
7.5 |
| 7 |
170 |
9.5 |
| 8 |
205 |
11.5 |
| 9 |
240 |
13.5 |
| 10 |
275 |
15.5 |
| 11 |
310 |
17.5 |
| 12 |
345 |
19.5 |
These estimates are based on DCCT data. An
updated version of this table, based on final results
of the ADAG Trial, will be available at www.diabetes.org
after publication of the study's findings in 2008 1.
1 Table 9 - Diabetes Care, Volume 31 Supplement 1, January 2008, S18
When will I need to have my A1C tested?
If you are meeting your treatment goals and have stable glucose control, the ADA recommends that an A1C test be done at least twice a year. If you change therapy or are not meeting your goals, the A1C test should be done every 3 months.
Is my A1C all I need to know?
A1C gives you an idea of your average blood sugar level over the past 3 months. Your blood sugar level fluctuates throughout the day, especially after meals. To adequately control your blood sugar levels, you may need to test your blood sugar daily, even multiple times a day, in order to determine how well your diabetes treatment is working for you. [See Feature Article A Do It Yourself Blood Test- The Importance of Blood Glucose and the Monitoring section of this website ]
Understanding your A1C goal is one important step in controlling diabetes. Your diabetes management team may include your doctor, a nurse, dietician and pharmacist. Your Rite Aid pharmacist is available to help you in your efforts.
