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Estimated Average Glucose (eAG)

Converting Your A1c to Numbers on Your Meter

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Updated March 05, 2010

Estimated Average Glucose (eAG)
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Estimated average glucose (eAG) is a term you may not be familiar with. The American Diabetes Association (ADA) has introduced this term to help us translate our A1c tests into numbers that would more closely represent our daily glucose meter readings.

Making Sense of eAG

To understand eAG, we need to begin with the A1c test (also known as glycated hemoglobin or HbA1c). The A1c test measures the amount of hemoglobin (the protein that carries oxygen) that has glucose attached to it in the red blood cells (glycated hemoglobin).

The problem is that the A1c test measures the amount of glycated hemoglobin as a percentage of total hemoglobin (an A1c of 7% means that 7% of the total hemoglobin has glucose attached to it), and our glucose meters measure glucose directly in the blood in milligrams per deciliter (150 mg/dl).

New research findings now provide an accurate way to calculate estimated glucose levels from the A1c results. This way we can use the same numbers we are accustomed to seeing on our daily glucose meters.

Below is a quick reference guide that will help you calculate your estimated average blood glucose level from your A1c result.

A1c Versus Daily Monitoring

While the A1c test is important for measuring your long-term blood glucose management, it can’t replace daily blood glucose tests. An A1c test won’t give your current blood sugar level. You need that important information in order to adjust your insulin, food intake and activity level. The A1c is a long-term management tool that should be used in addition to, and not as a substitute for, your daily blood sugar testing.

The American Diabetes Association recommends that you get an A1c test at least twice a year and preferably 4 times a year (quarterly).

eAG and the Average Glucose Reading on Meters

Most blood glucose meters used for daily testing can quickly give you an average of all the readings over the past several weeks or months. But this “average” is not the same as the eAG. Even if you test your blood ten times a day or more, you are only getting a reading of what your glucose is at that moment. This average from your glucose meter is likely to be lower than your eAG. Why? Because the eAG represents an average of your glucose levels 24 hours a day and over a much longer period of time. Therefore it is more accurate.

When you combine the eAG findings with your meter’s average, you are getting a valuable and more complete picture of your overall diabetes management.

Sources:

David M. Nathan, Judith Kuenen, Rikke Borg, Hui Zheng, David Schoenfeld, and Robert J. Heine, for the A1c-Derived Average Glucose (ADAG) Study Group. " Translating the hemoglobin A1c assay into estimated average glucose values." Diabetes Care Vol. 31, Num. 8, August 2008.

A1c (%) to eAG (mg/dl)
6.0% = 126 mg/dl
6.5% = 140 mg/dl
7.0% = 154 mg/dl
7.5% = 169 mg/dl
8.0% = 183 mg/dl
8.5% = 197 mg/dl
9.0% = 212 mg/dl
9.5% = 226 mg/dl
10.0% = 240 mg/dl

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