Estimated average glucose (eAG) or average glucose estimation is a way to read HbA1C blood test results to make it easier to understand. This method is considered more accurate for knowing and predicting blood sugar levels over time.
The hemoglobin A1C (HbA1C or A1C) test is a blood test to determine the average blood sugar level over the past 2-3 months. This test is done by measuring the percentage of blood sugar attached to hemoglobin. The more sugar attached to the hemoglobin, the higher the sugar level in the blood.
To make reading HbA1C test results easier to understand, the American Diabetes Association (ADA) introduced estimated average glucose (eAG) or estimated mean glucose.
Through this method, the HbA1C test results, which are initially in the form of a percentage, are converted to mg/dL or mmol/L which are similar to the results of daily blood sugar measurements.
Benefit Estimated Average Glucose (eAG)
The HbA1C test is commonly used to diagnose type 1 diabetes, type 2 diabetes, and prediabetes. A normal HbA1C result is 4–6% or 70–126 mg/dL in an eAG reading.
Meanwhile, diabetics are targeted to have an eAG of less than 154 mg/dL (HbA1C <7%), to reduce the risk of complications.
By knowing estimated average glucose (eAG) or daily glucose estimation, diabetics will get several benefits, including:
- Confirm the results of the self-test according to the doctor's recommendations
- Gives an overall picture of what treatment to take next
- Considering a healthy lifestyle that must be done to control blood sugar
- Tracks blood glucose levels over time
However, the normal values of HbA1C and eAG can be slightly different in each diabetic patient, because it is influenced by many factors, such as age, gender, and types of daily activities.
Convert HbA1C to eAG
The calculation of eAG is determined using a mathematical formula, namely by converting the percentage of HbA1C into the unit of measurement that you usually find in daily glucose measurements (mg/dL). The HbA1C to eAG conversion formula is as follows:
28.7 X HbA1C - 46.7 = eAG
The following is the conversion table for the percentage of HbA1C to eAG in mg/dL:
| A1C (%) | eAG (mg/dl) |
| 6 | 126 |
| 6,5 | 140 |
| 7 | 154 |
| 7,5 | 169 |
| 8 | 183 |
| 8,5 | 197 |
| 9 | 212 |
| 9,5 | 226 |
| 10 | 240 |
This number can be used as a reference to determine the condition of blood sugar levels in the body. The results of the conversion of HbA1C to eAG may not match the results of blood sugar measurements that you do yourself at home.
This is because the HbA1C test shows the average blood sugar for 2-3 months, while home blood sugar measurements are usually done when your blood sugar is low, for example before eating.
The eAG results can represent the average level of glucose in the blood over a longer period of time, making it more accurate than a daily blood sugar test.
according to American Diabetes Association, more than 25% of people with an HbA1C percentage of 5.5–6% are at high risk of developing diabetes within 5 years. Therefore, keep your blood sugar HbA1C calculation with the estimated average glucose (eAG) in the normal range and live a healthier lifestyle.
Things to Pay Attention to When Using Estimated Average Glucose
Although the measurement of blood sugar levels using the HbA1C test and eAG conversion is more accurate in monitoring the condition of diabetics, measurement by this method cannot be used if there are the following comorbidities:
- Kidney illness
- Sickle cell anemia
- Anemia
- Thalassemia
In addition, eAG also cannot be used if you are taking certain drugs, such as dapsone, erythropoietin, or iron.
The HbA1C test schedule is determined based on the type of diabetes, treatment plan, and how well the patient is meeting blood sugar targets. The following is the schedule for carrying out the HbA1C test based on the patient's condition:
- 1 time a year for people with prediabetes
- 2 times a year if you don't take insulin and your sugar levels consistently meet the target
- 4 times a year if taking insulin or having trouble keeping blood sugar levels on target
- As often as possible if you change your treatment plan or start taking a new diabetes medication
Estimated average glucose (eAG) or average glucose estimation can help people with diabetes monitor and control blood sugar levels, as long as it is accompanied by regular medication and a healthy lifestyle.
If you are having trouble understanding the conversion of HbA1C test results to estimated average glucose (eAG), do not hesitate to consult a doctor for an explanation.
