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Diabetes in Control: A1C and What it Means to You


By Alysa Ferguson, MS, RD, CDE

You may have heard your doctor talk about your A1C and wondered what it means. Hemoglobin A1C is a blood test that measures your average blood glucose over the past two to three months. It’s like a memory of your blood sugars, and it can tell you how you well you’re controlling your blood sugars over time. When A1C first reaches 5.7-6.4%, you are considered to have prediabetes. Once A1C hits 6.5%, you are considered to have diabetes. The goal for people with diabetes is to keep A1C under 7% to prevent complications.

A1C can be converted to estimated average glucose (eAG), by using a simple formula (28.7 X A1C – 46.7 = eAG) or you can use a calculator online ( The graph below gives you an idea of how A1C correlates to average blood glucose:

A1C Estimated average glucose
6% 126 mg/dl
6.5% 140 mg/dl
7% 154 mg/dl
7.5% 169 mg/dl
8% 183 mg/dl
8.5% 197 mg/dl
9% 212 mg/dl
9.5% 226 mg/dl
10% 240 mg/dl

For most people, your doctor will probably check your A1C every 3 months, or every 6 months may be sufficient if your blood sugar is in good control. If your doctor doesn’t discuss this number with you, make sure you ask what your number is, and discuss it with them. You can even request copies of your blood work so you can track your numbers over time. This is important because like blood sugar, A1C can tend to increase over time. It is recommended that you work with your health care provider to get to and stay within goal. If you’re not sure what you can do to get to goal, consider a consultation with a certified diabetes educator. They can help you evaluate what lifestyle changes may be helpful, such as controlling carbohydrate intake, increasing physical activity, losing weight, and managing stress. When lifestyle changes aren’t enough, medication changes are almost always needed. Diabetes changes over time, meaning many people need additional medication and/or insulin to control diabetes after many years, despite lifestyle changes. Talk with your health care team to find out which diabetes treatments are right for you.

For more information on this, and many other topics related to diabetes, visit If you live or work in Suffolk County, consider signing up for our Diabetes Self-Management Education Class Series. For more information, contact Jane Juran (631)727-7850 ext. 340 or

Alysa Ferguson is a Registered Dietitian, Certified Diabetes Educator and Family Health Educator with Cornell Cooperative Extension of Suffolk County’s Family Health and Wellness Program.


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