Understanding Your A1C Reading With Your eAG: Estimated Average Glucose

Patient Expert
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Every three to six months, we have our A1C or HbA1c measured. But what does that number really mean?

You know that it's a measure of your average blood sugar reading, but when was the last time your blood glucose monitor gave you a percentage? Your A1C is essentially measures the percentage of hemoglobin that is linked to glucose (hence the name glycated hemoglobin).

The Joslin Diabetes Center published an article about a way to report your A1C so you can translate that number to the numbers you see on your monitor, which is measured in mg/dL.

This is your eAG, or estimated average glucose.

So what does it mean when your doctor says your A1C is 8 percent? According to the Joslin article, an A1C of 8 percent means your eAG is about 183 mg/dL, which means your blood sugars usually run between 147 and 217 mg/dL.

My last A1C was 7.6 percent. This means my blood sugars run between 140 and 200 mg/dL on average throughout the day. The lowest A1C I've ever had was 6.2 percent, and the highest I've had was a few years ago when I started college, at 8.4 percent.

Here's a chart of A1C readings translated to eAG:

12 percent = 298 mg/dL (240 - 347)
11 percent = 269 mg/dL (217 - 314)
10 percent = 240 mg/dL (193 - 282)
9 percent = 212 mg/dL (170 - 249)
8 percent = 183 mg/dL (147 - 217)
7 percent = 154 mg/dL (123 - 185)
6 percent = 126 mg/dL ( 100 - 152)

So, if your A1C is 11 percent, your average glucose reading is 269 mg/dL, which means throughout the day, your blood sugar is between 217 to 314 mg/dL.

Numbers like these make it much more difficult to ignore that 11 percent. We all know we can't be feeling well or treating our bodies well if our blood sugars are between 200 and 300 mg/dL every day. That stress on our body will take a toll over time.

There have been times in my life when I was surprised that my A1C was as high as it was, and there were other times when I knew it was a direct result of how well or how poorly I was managing my blood sugars.

Either way, it's information. Don't let your number make you feel guilty if it's too high. Use it as information and set a goal for yourself to lower it as much as you can at your next appointment.

If your A1C has been higher than you'd like lately, take a closer look at your blood sugars throughout the day, try to check more often, and ask your health care provider about increasing your basal rates on your pump or your long-acting insulin dose. Even an increase of an extra two to three units over the course of one day can have a huge impact and really help you stay in range.

Like I said earlier, at different points in my life my A1C has been awesome, below 6.5 percent, and when life got a little crazy, like my first year in college, it was up in the 8 percent range! Everything is temporary. If you're willing to make an effort, learn more about your disease and consider yourself a lifelong work-in-progres, you wil see the results!