What Is the A1C Test for Diabetes?

Diabetes is a serious condition, but data from the CDC suggests that nearly 23% of adults in the U.S. who live with the condition don’t have an official diagnosis. That’s unfortunate because particularly with type 2 diabetes, many symptoms can be prevented, minimized, or alleviated through healthy lifestyle changes, like diet, exercise, sleep, and weight management.

First, you’ll want to be aware of several factors that can increase your risk of type 2 diabetes—like being 45 years old or older, overweight, and not regularly physically active, says the Centers for Disease Control and Prevention (CDC). Also, if someone in your family tree has type 2 diabetes (like a parent or sibling), that can increase your chances of developing it.

For those looking to get ahead of a type 2 diabetes diagnosis, getting tested, whether you feel healthy or not, is the key to catching diabetes early. The A1C test is a simple and effective option for diagnosing the condition, as well as routinely gauging how well your management plan is working, if you do have it. Read on to find out how this simple test can change your life!

“The A1C test, known as the hemoglobin A1C or HbA1c test, is a blood test that measures

your blood sugar levels over the last three months,” says Jonathan R. Genzen, M.D., Ph.D., a clinical professor of pathology at the University of Utah in Salt Lake City and chair of the College of American Pathologists’ Clinical Chemistry Committee. “It’s a crucial indicator for managing diabetes because it gives a long-term view of how well your blood sugar has been controlled.”

But how exactly does the test diagnose diabetes or even help spot prediabetes? High A1C levels can be indicative of an elevated risk of developing type 2 diabetes. That’s why, if your goal is to dodge a diagnosis, keeping your A1C levels within the healthy range is of the utmost importance.

The A1C test measures your blood glucose (sugar) levels by determining what percentage of your hemoglobin is coated with sugar, or “glycinated,” explains Libu Varughese, M.D., an endocrinologist at Memorial Hermann in Houston, TX.

“When we sample the hemoglobin, we’re looking at how much sugar is attached to it, leading to an estimation of the average blood sugars over the last three months,” says Dr. Varughese.

According to Dr. Varughese, hemoglobin can live in red blood cells for 90 to 120 days, and glucose attaches to hemoglobin over time to be transported around the body. If you think of hemoglobin as a car, glucose is a hitchhiker. “Everyone has red blood cells that carry oxygen to all of the other cells,” explains Dr. Varughese. “Hemoglobin is the oxygen-carrying protein in the blood.”

A blood sample is needed. This can be done either via a traditional blood draw through the vein or from a small prick of your fingertip, says endocrinologist Avantika Waring, M.D. chief medical officer at 9amHealth. Then, your sample is sent to a laboratory to be analyzed by pathologists and laboratory directors, says Dr. Genzen. If your A1C levels come back high, don’t worry—your doctor can help you figure out a game plan to help you bring them down.

Your results will fall into one of three A1C categories, according to all three experts. (You can also plug your blood results into this handy A1C calculator).

Normal - Below 5.7%

If your A1C comes back below 5.7%, that’s great—you’re considered in the normal range! “This indicates that your blood sugar is in a healthy range, and your body is managing it well,” Dr. Genzen says.

Prediabetes - Between 5.7% and 6.4%

A reading of 5.7% or higher but below 6.4% is typically considered prediabetic, meaning your risk of developing type 2 diabetes is heightened. That said, you aren’t fully in diabetes territory and there’s time to make some changes. “These levels are a sign of increased risk of developing type 2 diabetes, especially if no action is taken to manage blood glucose levels through lifestyle changes such as diet and exercise, and occasionally with the addition of medication,” Dr. Waring says.

Diabetes - 6.5% or higher

An A1C test that comes back with 6.5% or higher indicates diabetes, Dr. Waring notes. “When your blood glucose is elevated to this level, it suggests your body is not regulating glucose effectively.”

An A1C test is usually part of a basic lipid panel—the blood work you get at your annual check-up with your primary care provider. If it isn’t included and you’re considered at risk of diabetes, your doctor will likely order one for you separately. “The majority of patients are asymptomatic, which is why it’s important to get the test during your annual physical,” Dr. Varughese says. Indeed, people with type 2 diabetes often don’t exhibit symptoms for several years.

Our experts say that in addition to the main risk factors, there are several symptoms to watch out for that could indicate diabetes. Dr. Varughese adds that having one or more of these symptoms may mean the diabetes has already advanced.

Symptoms of diabetes include:

• Increased thirst

• Frequent urination

• Slow wound healing (think: cuts and bruises)

• Blurred vision

• Increased hunger

• Unexplained weight loss

• Unexplained weight gain

• Extreme fatigue

• Frequent infections

Also, if you’ve ever been pregnant and experienced gestational diabetes (which exclusively occurs during pregnancy) that can make you susceptible to having elevated blood glucose levels down the line.

The CDC recommends getting your A1C tested every three years (if not annually at your check-up) if you’ve had gestational diabetes, are over 45, or have any of the other main risk factors. If you already have a diabetes diagnosis, getting an A1C test at least twice a year can help ensure that your care plan includes effectively managing your blood sugar.

“In-range blood sugar levels in people with type 2 diabetes help reduce the risk of complications like kidney and eye disease and nerve damage,” Dr. Waring says. “So it’s very important that people who live with diabetes know their numbers and work closely with their physicians to keep levels in the healthy range.”