A1C, eAG, and What They All Mean: An Intro to A1C Levels and What to Expect

You might have already had an A1C test, or perhaps your doctor recently ordered it for the first time.

Whether you're familiar with checking your glucose levels at home or are just starting to learn about this, here’s a high-level overview of what A1C is and what you can expect next!

The A1C test is commonly used to diagnose diabetes and to help you and your doctor assess how well your current treatment plan is working. It gives a picture of your average blood glucose (or blood sugar) levels over the last two to three months. The test can also help identify prediabetes, which indicates a higher risk of developing diabetes. The higher your A1C, the greater the risk of developing complications such as heart disease, kidney disease, and nerve damage. This test is typically ordered twice a year by your provider, but they will inform you how often it should be done. Unlike some lab tests, A1C does not require fasting, making it a more convenient option for many patients!

How Does A1C Work?

Hemoglobin is a protein in red blood cells that plays a crucial role in transporting oxygen from your lungs to the rest of your body and returning carbon dioxide back to the lungs to be exhaled. It's also what gives blood its red color! When glucose enters your bloodstream, some of it naturally binds to hemoglobin, forming a molecule called glycated hemoglobin, or HbA1c. The more glucose present in your blood, the more glucose binds to hemoglobin, resulting in higher A1C levels.

What Do the Numbers Mean?

A1C levels are reported as percentages. The higher the percentage, the higher your average blood glucose levels have been over the past two to three months. The target A1C level can vary depending on a person’s age and other factors, so your target might differ from someone else’s. For most adults, the goal is to keep A1C below 7%. Here are the general guidelines from the American Diabetes Association:

A1C result range, retrieved from the American Diabetes Association. Link: Understanding A1C Test | ADA

A1C and “Estimated Average Glucose” (eAG)

You may have heard your provider use the term “estimated average glucose” or seen eAG on your lab results. The eAG is an estimate of your average blood glucose and is similar to what you might monitor at home with a glucometer. However, eAG/A1C is not the same as the average of your readings from a glucometer. A glucometer measures your blood glucose at a specific moment, whereas eAG and A1C reflect an average of your glucose levels over a 24-hour period.

Since red blood cells turn over every 120 days, the two- to three-month snapshot provided by the A1C test offers a better representation of your blood glucose levels over time.

Can Other Factors Cause High A1C?

Yes! While high blood glucose is the primary cause of elevated A1C, other factors can affect the test result. Here are some of them:

·         Hemoglobinopathies

·         Anemia

·         Chronic Kidney Disease

·         Pregnancy

·         Vitamin B12 Deficiency

·         Liver Disease & Alcohol Use

·         High Triglycerides or Lipid Abnormalities

·         Medications

·         Age

·         Shortened Red Blood Cell Lifespan

If your doctor suspects there could be other reasons for a high A1C, he or she will order additional testing. If you have a history of any of the above, let your doctor know prior to getting this test. If you are pregnant or think you may be pregnant, and your doctor does not already know, let them know. There is a separate test done to diagnose gestational diabetes that they may want to run, although this is usually done around 20 weeks gestation.

What to Expect from Your Results

• Below 5.7%: Congratulations! You don't have prediabetes or diabetes, but it's still important to maintain a healthy lifestyle.

• 5.7% - 6.4%: You’re considered prediabetic. Your doctor will help you create a plan focusing on healthier food choices, weight management (losing as little as 15 pounds can significantly lower your A1C!), and exercise.

• 6.5% or higher: You may be diagnosed with diabetes. Your doctor may do further tests to determine if you have type 1 (insulin-dependent) or type 2 (non-insulin dependent) diabetes. Treatment will vary depending on the type of diabetes you have. For type 2 diabetes, treatment typically starts with lifestyle changes and may progress to medications if necessary. A diet rich in non-starchy vegetables, lean proteins, whole grains (in moderation), healthy fats, and limited added sugars and processed foods is a good first step.

Navigating Your New Diagnosis

It’s completely normal to feel overwhelmed and unsure about your next steps—don’t worry! Your doctor can refer you to a nutritionist, and many insurance plans will cover this. Nutritionists can help you adjust to your new lifestyle and provide guidance on making sustainable changes without confusing you with complex terms like “macros” or “micros.”

And don’t stress about finding an intense workout program! A simple 30-minute walk each day is enough to help improve your blood glucose levels, much like taking a metformin tablet. If prescribed metformin, it helps improve insulin sensitivity and lower blood glucose levels.

You’ll likely need to start checking your blood glucose regularly. Your doctor may ask you to test your fasting blood glucose first thing in the morning and possibly several times throughout the day, especially before and after meals. If you find finger pricks uncomfortable, ask your doctor for smaller lancets—they are much less painful and still effective!

Though you can buy A1C tests online, it's usually best to schedule an appointment with your doctor, especially if you're over 35, overweight, had gestational diabetes, or have a family history of diabetes. They may recommend this test even if you don’t have symptoms.

Understanding A1C and how it reflects your blood glucose levels is an important step in managing your health. Whether you're in the normal range, dealing with prediabetes, or have been diagnosed with diabetes, there are steps you can take to keep your blood sugar levels in check. Regular monitoring, healthy lifestyle changes, and working with your healthcare team are key to managing your condition effectively. Remember, you're not alone in this journey—ask questions, seek support, and take it one step at a time!

References

American Diabetes Association - Understanding A1C Test | ADA