To understand what the eAG is, we first have to look at a test called A1c:

The A1c is a blood test, done in a lab, that shows what your average blood sugar has been for the past 3 months.

A1c is also known as: Glycosylated hemoglobin, glycohemoglobin, hemoglobin A1c, and HbA1c.

The glucose that the body doesn’t store or use for energy stays in the blood and attaches to red blood cells (RBCs), which live in the bloodstream for about 4 months. The lab test measures the amount of glucose attached to the red blood cells.

The amount is the A1c and is shown as a percentage. Your A1c number can give you and your health care team a good idea of how well you’ve controlled your blood sugar over the previous 2 to 3 months. When you get your A1c result you’ll also see another number called the estimated Average Glucose, or eAG.

Your estimated Average Glucose (eAG) number is calculated from the result of your A1c test. Like the A1c, the eAG shows what your average blood sugars have been over the previous 2 to 3 months, but instead of a percentage, the eAG is in the same units (mg/dl) as your blood glucose meter.

Reference ranges:

The below chart shows the correlating eAG level for different A1c results.

Interpreting results:

The important thing to note about your eAG and A1c is that while this information is very useful to gain an overall idea of your diabetes management, it is one piece of the puzzle regarding your blood sugar levels.

It is entirely possible to have an excellent A1c and eAG level and not have very good diabetes management. If you average together many high and low blood sugar readings, you will find that the result looks deceivingly good. This is why aside from getting our A1c test and taking note of the eAG level we also need to listen to our healthcare providers when they tell us to self monitor our blood sugars with a personal meter device. We get the best guidance from the combined power of both types of data.