An A1C reading can be helpful if you understand what it means about your daily blood glucose (sugar) levels.

Understanding how your A1c accumulates over the course of 2 to 3 months and how it translates to an actual average blood sugar level is a critical part of diabetes management.

In this article, we’ll discuss the significance of glycated hemoglobin as measured by your A1c, the broader context of how glucose can react with proteins in the body to form Advanced Glycation End-products (AGEs), how your A1c result translates to an estimated average glucose (eAG), and what you can do with that information.

A woman sitting on the ground checking her blood sugar level

Key Points:

  • The A1c test reflects the percentage of glycated hemoglobin (A1c) in your blood, offering an average of your blood glucose levels over the preceding 2 to 3 months.
  • This test specifically measures glycated hemoglobin, indicating your average blood glucose levels. It’s part of your body’s broader glucose metabolism, which in excess, can lead to the formation of AGEs.
  • Though not directly measured by the A1c test, AGEs are formed when sugars react with proteins or fats, potentially contributing to diabetes complications by damaging tissues, including blood vessels and nerves.
  • The eAG level is derived from your A1c results and reflects your average blood sugar in more familiar daily monitoring terms.
  • Personalizing your A1c and blood sugar targets in consultation with your healthcare team is important for effective diabetes management.

Table of Contents

What your A1c is really measuring: glycated hemoglobin

Your A1c reflects the percentage of glycated hemoglobin, or HbA1c, in your blood. Glycated hemoglobin forms when glucose in the bloodstream attaches to the hemoglobin in red blood cells. 

The higher the glucose levels in the bloodstream, the more that attaches to the red blood cell, thus the higher the A1c.

This process reflects the average blood glucose levels over the past 2 to 3 months, providing information on your glucose control.

It’s important to understand that while A1c provides a direct measure of glycated hemoglobin, consistently high A1c levels suggest prolonged exposure to high glucose levels, which may increase the risk of forming AGEs in the body.

These compounds can contribute to the blood vessel and nerve damage associated with the complications of diabetes, such as retinopathy (eye damage), neuropathy (nerve damage), and nephropathy (kidney damage).

Accordingly, consistently high blood glucose levels can lead to increased formation of AGEs, which in turn can contribute to diabetes-related complications.

However, it’s important to note that the A1c test specifically measures the amount of glucose that has attached to hemoglobin, serving as an indirect indicator of average blood glucose levels and potential for AGE-related damage over time.

What is an estimated average glucose level?

Before we start talking about A1c results, we need to help you understand one thing: your eAG.

Your eAG represents the average blood sugar level over a period, typically mirroring the timeframe of the A1c. 

Although you might not hear the term eAG frequently in your doctor’s office, it plays a significant role if you’re aiming to improve your A1c and minimize the risk of diabetes complications.

It’s important to understand that blood sugar levels naturally fluctuate throughout the day due to various factors such as what you eat, activity, and stress. Therefore, eAG is not a fixed number that your blood glucose levels adhere to at all times. 

Instead, think of eAG as an overall average that smooths out these daily ups and downs to provide a more comprehensive picture of your glucose control over time. This average is a useful tool for assessing how well your diabetes management plan is working and making necessary adjustments.

Now, let’s dive deeper into how this all ties together…

Translating your A1c to a blood sugar level

Seeing an A1c result of, say, 8.0 percent might lead some to believe their glucose levels are consistently within their target range. However, a deeper look into what an A1c of 8.0 percent really translates to in terms of average blood sugar might reveal a different story.

An A1c of 8.0 percent corresponds to an eAG of approximately 183 mg/dL (10.1 mmol/L). This average is significantly higher than the ADA-recommended target for most non-pregnant adults, which is an eAG of less than 154 mg/dL (less than 8.6 mmol/L) or an A1c of less than 7.0 percent.

The discrepancy between an in-the-moment glucose reading and the 3-month average reflected by A1c can be surprising and highlights the importance of understanding both measures in diabetes management.

By translating your A1c into an eAG, you gain a clearer picture of your overall blood sugar management, beyond what daily readings can show. This additional perspective is helpful for making informed adjustments to your diabetes care plan.

You can use this simple eAG/A1c conversion chart from the American Diabetes Association (ADA) to instantly translate your latest A1c result into more easily understandable eAG results.

A1c to eAG chart

A1ceAG (mg/dL)eAG (mmol/L)
5 percent975.4
6 percent1267.0
7 percent1548.6
8 percent18310.2
9 percent21211.8
10 percent24013.4
11 percent26914.9
12 percent29816.5

In general, the ADA recommends a fasting blood sugar level of 80 to 130 mg/dL (4.4 to 7.2 mmol/L), a blood sugar level 1 to 2 hours after meals of less than 180 mg/dL (10.0 mmol/L), and an A1c of less than 7.0 percent in people with diabetes.

Read more about blood sugar levels in: What Are Normal Blood Sugar Levels? and more about blood sugar and A1c levels in Blood Sugar Chart: Blood Sugar and A1c targets. 

Determining your own A1c and eAG goals

In an ideal world, our A1cs would all be a magical 5.0. But managing diabetes can be challenging.

This means that determining the right A1c goal for you, your body, and your life as a person with diabetes is a very personal decision that you and your healthcare team must work together to decide on.

For instance, someone with a history of hypoglycemia unawareness (the inability to detect the early signs of low blood glucose) may find a target A1c of 6.0 percent to be too dangerous, putting them at too much risk for severe hypoglycemia.

Someone who lives by themselves may find that sleeping with blood sugars lower than 120 mg/dL, for example, puts them at higher risk for hypoglycemia.

For people who have been running blood glucose levels higher than 240 mg/dL, the goal may be to gradually lower their blood glucose levels with the help of their healthcare team.

This means their A1c is going to be set at a higher target than “normal,” too.

Whatever your blood sugar targets, they should be periodically reviewed and adjusted, as necessary, in collaboration with your healthcare team to reflect any changes in your health status, lifestyle, or diabetes management needs.

Find out more about generally recommended A1c levels in: What Is a “Normal” HbA1c? and What Is a Dangerous Level of A1c?

How often should you have an A1c test?

If you are living with diabetes, your healthcare provider may order an A1c test for you somewhere between two and four times a year, depending on factors such as your level of blood sugar management and frequency of severe hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar).

Learn about home A1c tests in: How to Measure Your A1c at Home.

Final thoughts

Everyone is in a different place with their diabetes management, and we all have different personal needs, challenges, and goals. And that’s OK. Work closely with your healthcare team, and focus on what’s right for you and your current life as a person with diabetes.