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A bead of blood on a fingertip.
A bead of blood on a fingertip.

What Is Your A1C?

An Essential Tool for Measuring Your Health

Your A1C is more than just a medical term. It’s a critical number that can provide insight into your overall health.

The A1C test, also known as Hemoglobin A1C or HbA1c test, measures your average blood sugar levels over the past three months. The test looks at how much glucose (sugar) is attached to hemoglobin, a protein in your red blood cells. The result is expressed as a percentage, which represents the average blood sugar level during that time period. The higher your blood sugar levels, the more glucose binds to hemoglobin, resulting in a higher A1C reading.

Why Is A1C Important?

  • Longer-term assessment: Unlike a fasting glucose test that measures your blood sugar level at a single moment in time, the A1C test measures your blood sugar control over a three-month period and does not require fasting. This provides a bigger picture of how your body is regulating blood sugar and can identify trends and patterns that might otherwise be missed.
  • Diabetes diagnosis: The A1C test plays an important role in diagnosing prediabetes and diabetes.  
    • A normal A1C level is below 5.7%
    • A level of 5.7% to 6.4% indicates prediabetes
    • A level of 6.5% or more indicates diabetes
  • Risk assessment: The higher your A1C level, the greater your risk of developing diabetes complications such as heart disease, stroke, kidney disease, eye problems and nerve damage. “Early detection allows for timely intervention and lifestyle changes,” says Amina F. Basha, MD, an endocrinologist at Northwestern Medicine.
  • Treatment monitoring: If you are already diagnosed with diabetes, the A1C test can gauge the effectiveness of your treatment plan and indicate if adjustments are needed.

When Should You Get the A1C Test?

The frequency of A1C testing varies depending on your health condition and risk factors. Generally, it’s recommended to have the test if you fall into any one of the following categories:

  1. You are over the age of 45. The Centers for Disease Control and Prevention (CDC) recommends a baseline A1C test for adults in this age range.
  2. You are at risk of diabetes. Risk factors include:
    • A family history of diabetes
    • Carrying excess weight
    • Low physical activity
    • Gestational diabetes during a pregnancy
    • Having non-alcoholic fatty liver disease
    • Race or ethnicity: People who are Black, Latin American, American Indian, Alaska Native, Pacific Islander or Asian American are at higher risk.
  3. You are diagnosed with prediabetes or diabetes.
  4. You are experiencing symptoms of diabetes, including:
    • Unexplained weight loss
    • Frequent urination
    • Excessive thirst
    • Fatigue
    • Slow-to-heal cuts
    • Blurred vision

Is Prep Work Required Before Testing?

“Because the A1C blood test does not require any fasting, you do not need to do anything special to prepare,” says Dr. Basha. For the test, blood is drawn from your finger or arm at your physician’s office or laboratory.

Can You Lower Your A1C?

“Type 2 diabetes and prediabetes are both reversible,” says Dr. Basha. “I've seen patients’ A1C come down from 9% to the fives. Anything below 5.7% is normal.”

The following lifestyle changes can help lower your A1C:

  • Eat a balanced diet that includes complex carbohydrates like whole grains, beans, vegetables and fresh fruits. Your body digests complex carbohydrates more slowly and releases glucose into your blood stream more gradually. Incorporate lean proteins and healthy fats into your meals for sustained energy.
  • Monitor portion sizes to avoid overeating. “A good rule of thumb is making sure your plate is half non-starchy vegetables, one quarter protein and one quarter carbohydrates,” says Dr. Basha.
  • Exercise regularly. Aim to exercise at least 20 minutes every day. “I encourage patients to use a pedometer or some sort of tracking device to stay accountable,” says Dr. Basha.
  • Cut down or eliminate alcohol consumption.
  • Stop smoking.
  • Make sure you are getting at least seven hours of sleep each night. Too little sleep can increase insulin resistance.

Depending on your health condition and test results, your physician may also recommend medication.

“The A1C test is a valuable tool in managing your health,” says Dr. Basha. “The test’s ability to provide a broader view of your blood sugar control over time can help you and your care team make informed decisions about your lifestyle and medications.”