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 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 a measurement of the advanced glycogenated end-products (AGE) that have accumulated in your blood from blood sugar levels: the higher our blood sugars are, the more AGE are present in our blood. AGE are also what lead to various complications we're warned about: nerve damage, retinopathy, etc.

So, as usual, our goal is to reduce our A1C, which will reduce our AGEs, and we do this by controlling our blood sugars better.

The Joslin Diabetes Center published an article about a new way to report your A1C so you can translate that number to the numbers you see on your monitor.

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 183, which means your blood sugars usually run between 147 to 217.

My last A1C was 7.6 percent. This means my blood sugars run between 140 to 200 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 (240 - 347)
11 percent = 269 (217 - 314)
10 percent = 240 (193 - 282)
9 percent = 212 (170 -249)
8 percent = 183 (147 - 217)
7 percent = 154 (123 - 185)
6 percent = 126 ( 100 - 152)

So, if your A1C is 11 percent, your average glucose reading is 269, which means 95 percent of the day, your blood sugar is between 217 to 314.

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 every day. That stress on our body, and the continual accumulation of AGE, 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 think 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!