If you have diabetes, you might have heard your doctor or healthcare professional mention estimated average glucose (eAG).
But, what exactly is eAG, what does it tell you about your blood sugar levels, and why’s it important? This article will help answer these questions and explain why it’s helpful to know what your eAG is if you have diabetes.
Estimated average glucose (eAG) refers to your average blood sugar (glucose) levels for the past 60 to 90 days. It can be reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L).
To measure your eAG, you’ll need to take an A1C blood test.
Unlike your daily blood glucose readings that measure your blood sugar level at that moment, eAG looks at the bigger picture. Your eAG measures your typical blood sugar level over the past few months.
Knowing your eAG can help with the following aspects of diabetes management:
- diagnosing both prediabetes and diabetes
- corroborating daily blood glucose monitoring results
- determining whether your diabetes treatment plan is helping
- making changes to your diabetes treatment plan
- reinforcing healthy lifestyle and diet choices
Once you know your A1C percentage, you can use the following chart to look up your eAG:
Alternatively, you can use this online calculator from the American Diabetes Association (ADA) to determine your eAG using your A1C and vice versa.
There’s a direct relationship between A1C and eAG values, as represented by the following formula:
eAG (mg/dL) = 28.7 x A1C – 46.7
In general, both A1C and eAG readings provide the same information about your recent blood glucose levels, for instance, whether your treatment plan is helping.
But eAG uses the same units (mg/dL or mmol/L) that you regularly see on your daily blood sugar readings, making it easier to interpret.
There’s no single eAG target for everyone. Your doctor will help you determine an appropriate target according to your age and circumstances. In addition, your target eAG may change over time.
In general, most non-pregnant adults with diabetes are encouraged to maintain an eAG below 154 mg/dL (8.6 mmol/L). That corresponds to an A1C test result that’s less than 7 percent.
The ADA defines the following eAG ranges:
- Normal range: less than 114 mg/dL
- Prediabetes range: greater than 114 mg/dL and less than 140 mg/dL
- Diabetes range: greater than 140 mg/dL
As indicated above, higher eAG values indicate higher average blood glucose levels over the past few months. If you’re in the prediabetes or diabetes range, you may be at an increased risk of developing diabetes complications.
If your eAG value is higher than your target, it could be an opportunity to improve your personalized treatment plan.
It’s important to talk with your doctor or healthcare professional about what you believe is working and what isn’t. Your doctor can then make changes to your plan as necessary.
According to the 2021 diabetes care guidelines provided by the ADA, people with well-controlled diabetes should undergo an A1C blood test to determine their eAG at least twice per year.
The same guidelines suggest testing at least 4 times per year for individuals whose treatment plan has recently changed, along with those who are having difficulty meeting their blood sugar targets.
Daily glucose monitoring is another critical tool in diabetes management. But daily monitoring doesn’t give you a long-term view of your blood glucose levels.
The readings on your monitor provide a snapshot of your blood sugar at a particular point in time. Your monitor might automatically calculate an average of all of these readings. But this number isn’t the same as your eAG.
Your eAG accounts for your blood glucose levels 24 hours per day, including the times when you’re not likely to test. As the name suggests, it’s an estimate based on your A1C test results.
If you have diabetes, you’re typically instructed to test your blood sugar when it’s low (for example, when you wake up, before a meal, or several hours after a meal). Your eAG is likely higher than the average on your monitor, providing a broader view of your blood sugar levels.
Your eAG can help both you and your healthcare team understand your blood glucose levels over a 60- or 90-day period.
To know your eAG, you’ll have to take an A1C blood test. Your eAG is reported in the same units that you typically see on your blood sugar meter, making it simple to interpret.
Your doctor will help you determine an appropriate eAG target based on your age and additional factors. Depending on your eAG reading, your doctor may make changes to your diabetes treatment plan.
Photo by Artem Podrez: