Diabetes and the Significance of the A1c Test: Part 2 in a Series

Audrey Demmitt and her dog guide

Audrey Demmitt, RN, BSN, is a nurse diabetic educator, VisionAware Peer Advisor and author of the VisionAware multi-part blog series on diabetes and diabetes education. At age 25, Audrey was diagnosed with retinitis pigmentosa and continued to work as a nurse for 30 years with her visual impairment.

She has worked as an Adjustment to Blindness Counselor and Diabetic Educator for Vision Rehabilitation Services of Georgia and as a school nurse providing in-service training for school staff and developing care plans for newly-diagnosed students and their families.

In Part 1 of her series, Audrey discussed how diabetes education can help lower your blood sugars and reduce the risk of diabetic retinopathy. In this week’s Part 2, Audrey emphasizes the significance of the A1c test in the effective diagnosis, treatment, and management of diabetes. As Audrey says, “By making daily efforts to stick to your treatment plan and making healthy lifestyle changes, you can achieve your A1c goal, avoid long-term complications, and live well with diabetes.”

How Diabetes Is Diagnosed

When teaching people with diabetes, I encourage them to “know their numbers” and use them to better manage their diabetes. Let’s take a look at the A1c and why it is an important number.

Diabetes is a complex condition to diagnose and manage. In the early stages, there are no symptoms and in the long term, there can be devastating effects on every system in the body. Prevention, early detection, and vigilant management are key factors in reducing diabetes complications, such as blindness and blood vessel disease.

The A1c blood test, also known as glycated hemoglobin, hemoglobin A1c, and HbA1c, is the primary tool used to diagnose diabetes and pre-diabetes and to monitor blood glucose control in people with type 1 and type 2 diabetes. This test enables health care providers to diagnose diabetes and treat it before complications occur and to diagnose pre-diabetes to prevent or delay the development of type 2 diabetes. Below are the established A1c levels used to diagnose diabetes and pre-diabetes:

DiagnosisA1c level
Normalbelow 5.7 percent
Pre-diabetes5.7 to 6.4 percent
Diabetes6.5 percent or above

What Does the A1c Measure?

The A1c test reflects a person’s average blood glucose – or sugar in the blood – for the past three months. When glucose enters the bloodstream, it attaches itself to hemoglobin, a protein in red blood cells. The A1c test measures what percentage of your hemoglobin is coated with sugar or “glycated.”

A normal A1c is below 5.7%. This number represents an average of all the ups and downs in blood glucose levels as if recorded on a video camera over the past many weeks. The higher the A1c, the higher the blood glucose levels have been over time and the higher your risk is for diabetes complications.

lab tech examines vial of blood image credit to National Eye Institute

How Does the A1c Compare to Other Blood Glucose Tests?

There are several other traditional blood glucose tests that are used to diagnose and manage diabetes: the fasting and random blood glucose tests, the glucose tolerance test, and the self-monitoring home glucose test. These can be thought of as snapshots, measuring the blood sugar level in a moment of time or day to day.

Normal blood glucose levels range from 80-100mg/dL (milligrams per deciliter), fluctuating throughout the day in response to food, activity, medication, illness, and stress. Daily readings are interpreted in the short term to monitor blood sugar changes. It is helpful to do daily testing and record the values to reveal patterns and responses so that you can take corrective actions and make adjustments to your daily care plan.

In contrast, A1c is a long-term average of blood glucose levels and gives a “big picture” perspective on how well you are doing in controlling daily blood sugars. It can be useful in evaluating the overall success of the treatment plan, your daily efforts and the efficacy of medications.

How Does the A1c Relate to My Daily Blood Sugars?

Your A1c can be converted to a number that is expressed in the same terms as your daily blood glucose readings. This is called “estimated average glucose” or eAG. For example, an A1c of 7% is equivalent to an estimated average glucose (eAG) of 154 mg/dL, reflecting blood sugars that may have ranged between 180 and 140 mg/dL over the past three months.

The A1c/eAG is not the same as the average blood glucose you may see on your meter, since it is an average of all the blood sugar levels – not just the ones you may have recorded on your meter. The average blood glucose reported on your meter is likely to be lower than your actual A1c/eAG.

Maintaining blood sugars as close to normal range as possible is the goal to reduce risks and complications of diabetes. When daily blood sugars are kept in optimal range, the corresponding A1c will also be optimal. Below is a table with conversions of A1c levels to eAG.

A1c in percenteAG in mg/dL

(Source: Adapted from American Diabetes Association. Standards of medical care in diabetes—2014. Diabetes Care. 2014;37(Supp 1):S14–S80, table 8.)

How Often Should my A1c Be Tested?

The American Diabetes Association (ADA) recommends you have the A1c test twice a year if your blood sugars are stable and you are meeting your treatment goals. Health care providers may repeat the A1c test as often as four times a year if there are changes in treatments or you are not meeting your A1c target. The A1c is like a report card on how well you are managing your diabetes.

What Should My Target A1c Be?

Everyone will not have the same A1c target. It will depend on your individual diabetes history and general health. You and your doctor need to discuss this and set goals that are appropriate for your situation.

The ADA suggests a target A1c below 7%. Research shows that keeping A1c levels below 7% can reduce complications of diabetes. But an A1c of 7% or below may not be safe or realistic for everyone. Less strict control may be suitable for elderly persons, those who experience severe hypoglycemic (low blood sugar) episodes, or those who already have advanced diabetes complications, for example.

People who are younger and have had diabetes for a shorter time may have a target A1c of 6.5% or below, according to the ADA recommendations. The key is to make sustained daily efforts to achieve the target that is best for you.

How Can I Meet My A1c Target?

Managing diabetes requires a lifestyle of healthy self-care practices. The keys to bringing down A1C levels are the same as for bringing down blood sugar levels. The essentials are:

  1. Taking the right medications at the right times and in the proper doses. Work with your doctor to evaluate your medications periodically. Adjust them when needed. Diabetes is a progressive disease. You will likely need to increase and/or add to your glucose-lowering medications over time.
  2. Eating the right portions of fruits, vegetables, whole grains, low-fat dairy, and healthy fats. A diet rich in fiber may lower blood sugar levels. You may want to learn more about counting carbohydrates and portion control. Eat about the same amount of carbs at each meal and at the same times each day. Ask a dietician to help you create a meal plan that will help control your weight and A1c.
  3. Increasing daily physical activity. Engage in at least 30 minutes of moderate exercise. For example, walk briskly five days per week and strength train two days per week. Find ways to move more and incorporate activities you enjoy into your day.
  4. Managing stress and depression. Negative emotions, depression, and diabetes burnout can make following your treatment plan difficult. If you are finding it hard to cope with diabetes, let your doctor know. Additionally, enlist the support of a loved one. There are many resources to help you.

Additional Resources

Make daily efforts to stick to your treatment plan and make healthy lifestyle changes. You can achieve your A1c goal, avoid long-term complications, and live well with diabetes. Here are some additional resources:

Mayo Clinic Tests and Procedures

Diabetic Living Online