What Does HbA1c Mean, and How Do You Interpret Your Test Results?

Diabetes is a common health condition in the U.S. and around the world. Healthcare professionals commonly use hemoglobin A1C (HbA1c or A1C) testing to diagnose diabetes. Compared to other tests used to diagnose diabetes, an A1C test is more convenient because you don’t need to fast (have no food or drink) the night before.

Here’s what you need to know about A1C, how to interpret the results, and why it’s useful to track — especially if you have diabetes.

What is A1C?

A hemoglobin A1C, or glycosylated hemoglobin, is a lab test that measures your average blood glucose over the past 3 months. This is different from a blood glucose test, which measures the amount of glucose (sugar) in your blood at the moment of testing.

It’s normal for blood glucose levels to change throughout the day, based on your level of activity and what you eat. An A1C test is useful because it gives information about your blood glucose levels over time, instead of at a specific moment.

What is the relationship between blood sugar and A1C?

The higher your blood glucose level over time, the higher your A1C will be. In the following table, you can see what your estimated average blood glucose has been based on your A1C test result.

Here’s the science on how that works. Hemoglobin — the protein in your red blood cells that helps carry oxygen in the blood — has an A1C component that sticks to glucose.

When your blood glucose is running high, more glucose will stick to your red blood cells. Your A1C number goes up.

Because a red blood cell lives for about 3 months, an A1C test paints a pretty accurate picture of blood glucose levels during that period of time.

How are A1C levels used to diagnose diabetes and prediabetes?

A1C testing is used to screen for high blood glucose levels. If an A1C is higher than normal, this could mean a person has prediabetes or diabetes.

Here’s how to interpret A1C levels:

• Normal: 5.6% or less

• Prediabetes: 5.7% to 6.4%

• Diabetes: 6.5% or higher

Who needs an A1C test?

A healthcare professional may recommend an A1C test for you based on your age, medical conditions, or risk factors. In general, people who may need an A1C test include:

• Everyone over age 45 as part of routine health screening

• Anyone with symptoms of diabetes like increased thirst, appetite, urination, or weight loss (among other symptoms)

• Anyone with a history of diabetes or prediabetes

• Anyone with a history of polyendocrine metabolic ovarian syndrome (PMOS), formerly called polycystic ovary syndrome (PCOS)

• Anyone with an increased risk of diabetes due to family history 

• Any woman with history of gestational diabetes

• People with signs of metabolic syndrome (obesity, high blood pressure, and/or high cholesterol)

• People with heart disease

A healthcare professional may also have other reasons for wanting to order an A1C test based on your history or physical exam.

A1C monitoring for people with diabetes

If you have diabetes, you’ll likely be used to monitoring your A1C levels every 3 months. This gives your care team a good idea of how your diabetes is responding to your treatment plan.

Many people with diabetes don’t have a “normal” A1C, but they’ll have a target A1C to aim for. It’s common for the target to be an A1C less than 7%, according to the American Diabetes Association. 

But your A1C goal might be higher: as high as 8% or 8.5%. This may be the case for people who are older or have other complex medical issues.

How is the A1C test performed?

An A1C test requires a blood sample. This is sent to a lab for testing. In some settings, you may be able to get an A1C home test kit or a “point-of-care” test. This gives you results in real time that you can discuss with your healthcare team right away.

Depending on the type of A1C test, you may expect to have a regular blood draw from a vein. For this test, a needle is inserted into your arm and a small amount of blood is taken in a tube and sent to a lab. If a point-of-care test is done, a healthcare team member will prick your fingertip and collect a few drops of blood. Then they’ll put this sample into a machine in the office. After a few minutes, it prints an A1C result.

How accurate are A1C results?

In general, A1C results are fairly accurate. A1C tests completed by a medical lab after a venous blood draw tend to be the most accurate, followed closely by the fingerstick blood test done within a healthcare professional’s office. Some at-home tests are considered reasonably accurate for following A1C trends, but none achieve the national standard for accuracy. It’s best to have your A1C test done by your healthcare team for the best results.

What A1C levels need medication or treatment?

There’s no specific A1C level that makes it necessary for you to take medication. You and your healthcare team will plan a treatment approach that’s best for you. This can be different for different people.

Some people with an A1C of 6.5% or higher may not take prescription medications, while others may get treatment for a lower A1C. It all depends on your individual health needs and the health goals you set with your care team.

What are the consequences if high A1C levels are left untreated?

Left undiagnosed and untreated, diabetes can cause long-term health complications. Over time, high levels of glucose in the bloodstream can damage both large and small blood vessels and lead to serious damage to nerves and vital organs throughout the body.

Large blood vessel damage is called macrovascular disease. It causes health problems similar to people with high blood pressure and high cholesterol, such as:

• Heart attacks

• Strokes

• Poor blood flow to limbs (peripheral arterial disease)

Small blood vessel damage is called microvascular disease. It causes complications like:

• Vision loss

• Nerve damage (neuropathy)

• Kidney damage

Over time, high levels of glucose also make it more difficult for the immune system to work correctly and increases the risk for infections.

Lifestyle tips to help maintain good A1C levels

There are lots of different ways to lower your A1C without medication.  Here are some ways to get started:

• Change what you’re eating. This is a big one. Your A1C will naturally drop if you’re able to eat less of certain foods (like sweets and simple carbohydrates) and eat more of other foods, like healthy fats, lean proteins, and complex carbohydrates.

• Move your body. Exercise is a great tool to improve your overall health. And it can help to lower your A1C too.

• Lose excess weight. Weight loss isn’t easy. But it can be an effective way to improve the way your body regulates blood glucose levels.

• Find support in your community. Diabetes is common. Chances are there are people in your community who have faced similar health challenges and can support you in your journey.

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Written by:

Meg Burke, MD

Meg Burke, MD, is a practicing primary care geriatrician in the Denver, Colorado area. She is board-certified in internal medicine and geriatric medicine, and received her undergraduate and medical degrees from Georgetown University in Washington, D.C. After graduating from medical school, Dr. Burke completed her internal medicine residency at Johns Hopkins Bayview Medical Center and her two years of subspecialty training in geriatric medicine at the Johns Hopkins Hospital in Baltimore, Maryland.

Edited by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

Reviewed by:

Frank Schwalbe, MD

Frank Schwalbe, MD, is an assistant professor of anesthesiology at the Yale School of Medicine. He has practiced anesthesiology for 30 years.

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