All About Your A1C

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What has your blood sugar been up to lately? Get an A1C test to find out your average levels—important to know if you’re at risk for prediabetes or type 2 diabetes, or if you’re managing diabetes.

The A1C test—also known as the hemoglobin A1C or HbA1c test—is a simple blood test that measures your average blood sugar levels over the past 3 months. It’s one of the commonly used tests to diagnose prediabetes and diabetes, and is also the main test to help you and your health care team manage your diabetes. Higher A1C levels are linked to diabetes complications, so reaching and maintaining your individual A1C goal is really important if you have diabetes.

What Does the A1C Test Measure?

When sugar enters your bloodstream, it attaches to hemoglobin, a protein in your red blood cells. Everybody has some sugar attached to their hemoglobin, but people with higher blood sugar levels have more. The A1C test measures the percentage of your red blood cells that have sugar-coated hemoglobin.

Who Should Get an A1C Test, and When?

Testing for diabetes or prediabetes:
Get a baseline A1C test if you’re an adult over age 45—or if you’re under 45, are overweight, and have one or more risk factors for prediabetes or type 2 diabetes:

• If your result is normal but you’re over 45, have risk factors, or have ever had gestational diabetes, repeat the A1C test every 3 years.
• If your result shows you have prediabetes, talk to your doctor about taking steps now to improve your health and lower your risk for type 2 diabetes. Repeat the A1C test as often as your doctor recommends, usually every 1 to 2 years.
• If you don’t have symptoms but your result shows you have prediabetes or diabetes, get a second test on a different day to confirm the result.
• If your test shows you have diabetes, ask your doctor to refer you to diabetes self-management education and support services so you can have the best start in managing your diabetes.

Managing diabetes:
If you have diabetes, get an A1C test at least twice a year, more often if your medicine changes or if you have other health conditions. Talk to your doctor about how often is right for you.

How to Prepare for Your A1C Test

The test is done in a doctor’s office or a lab using a sample of blood from a finger stick or from your arm. You don’t need to do anything special to prepare for your A1C test. However, ask your doctor if other tests will be done at the same time and if you need to prepare for them.

Your A1C Result

Diagnosing Prediabetes or Diabetes

A normal A1C level is below 5.7%, a level of 5. 7% to 6.4% indicates prediabetes, and a level of 6.5% or more indicates diabetes. Within the 5.7% to 6.4% prediabetes range, the higher your A1C, the greater your risk is for developing type 2 diabetes.

Managing Diabetes
Your A1C result can also be reported as estimated average glucose (eAG), the same numbers (mg/dL) you’re used to seeing on your blood sugar meter:

What Can Affect Your A1C Result?

Get your A1C tested in addition to—not instead of—regular blood sugar self-testing if you have diabetes.

Several factors can falsely increase or decrease your A1C result, including:

• Kidney failure, liver disease, or severe anemia.
• A less common type of hemoglobin that people of African, Mediterranean, or Southeast Asian descent and people with certain blood disorders (such as sickle cell anemia or thalassemia) may have.
• Certain medicines, including opioids and some HIV medications.
• Blood loss or blood transfusions.
• Early or late pregnancy.

Let your doctor know if any of these factors apply to you, and ask if you need additional tests to find out.

Your A1C Goal

The goal for most people with diabetes is 7% or less. However, your personal goal will depend on many things such as your age and any other medical conditions. Work with your doctor to set your own individual A1C goal.

Younger people have more years with diabetes ahead, so their goal may be lower to reduce the risk of complications, unless they often have hypoglycemia (low blood sugar, or a “low”). People who are older, have severe lows, or have other serious health problems may have a higher goal.

A1C: Just Part of the Toolkit

A1C is an important tool for managing diabetes, but it doesn’t replace regular blood sugar testing at home. Blood sugar goes up and down throughout the day and night, which isn’t captured by your A1C. Two people can have the same A1C, one with steady blood sugar levels and the other with high and low swings.

If you’re reaching your A1C goal but having symptoms of highs or lows, check your blood sugar more often and at different times of day. Keep track and share the results with your doctor so you can make changes to your treatment plan if needed.

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Test, levels, and more for diabetes

The A1C test is a blood test that measures a person’s average blood glucose or blood sugar levels over the past 3 months. An A1C reading of over 5.7% may be a cause for concern, but this will depend on various factors.

Doctors use the A1C test to check for prediabetes and diabetes. A range of 5.7–6.5% suggests a person may have prediabetes. Over 6.5% indicates diabetes.

This test also helps doctors monitor blood glucose levels in people with diagnosed diabetes.

Keeping A1C levels within the normal or target range lowers the risk of developing diabetes or its complications. Read on to learn what A1C test results mean.

The A1C chart below can help a person convert and understand their A1C test results. The doctor can provide more context and describe ways to keep blood glucose levels in a safe range.

Share on PinterestMNT-infographic_guide illustration by Diego Sabogal a1c-chart

The A1C test is also known as the:

• hemoglobin A1C, or HbA1c, test
• glycated hemoglobin test
• glycohemoglobin test

The A1C test measures the percentage of red blood cells that have glucose-coated hemoglobin. This measurement gives doctors an idea of the person’s average blood glucose levels over the past 2–3 months.

Hemoglobin is an iron-rich protein in red blood cells. It helps carry oxygen from the lungs to other tissues.

When glucose enters the blood, it binds to hemoglobin. The more glucose in a person’s bloodstream, the more hemoglobin is bound to glucose.

Undergoing the A1C test is straightforward: A healthcare professional takes a blood sample and sends it to a laboratory for testing.

A doctor may order this test to:

• diagnose prediabetes
• diagnose type 1 or type 2 diabetes
• monitor the blood glucose levels of a person with diabetes to check how well their treatment is working

If a person takes insulin to manage diabetes, their doctor may also ask them to monitor their blood glucose levels at home with a blood glucose meter or continuous glucose monitor.

In this case, the person still needs to undergo regular A1C testing.

Traditionally, A1C levels are reported as a percentage. Alternately, they may be reported as estimated average glucose (eAG), in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L).

Blood glucose meters and continuous glucose monitors also give eAG readings, some from at least 12 days of data.

The A1C test gives a more accurate long-term average. It takes into account fluctuations throughout the day, such as overnight and after meals.

A normal A1C level is below 5.7%. Normal eAG is below 117 mg/dL or 6.5 mmol/L.

If someone’s A1C levels are higher than normal, they may have diabetes or prediabetes. Their doctor might order a repeat test to confirm this.

Target levels in people with diabetes

A doctor will set a person’s target A1C level based on many factors. The right target varies from person to person.

For someone with diabetes, the target A1C level may depend on:

• the person’s age
• their overall health
• whether they are pregnant
• how long they have had diabetes
• their prescribed treatment plan
• any history of adverse effects from the treatment, including episodes of low blood glucose, or hypoglycemia
• any complications from diabetes
• the person’s preferences and treatment priorities

In general, a doctor might recommend aiming for A1C levels under 6. 5% if a person:

• is young and has a long life expectancy
• has had diabetes for a short period
• is effectively managing their diabetes with lifestyle changes or metformin alone
• is otherwise in good health

A doctor might recommend A1C targets of 7.0–8.5% if a person:

• is older and has a shorter life expectancy
• has had diabetes for a longer period
• has diabetes that is hard to manage, even with multiple medications
• has a history of severe hypoglycemia or other adverse effects of treatment
• has experienced complications of diabetes
• has other chronic health conditions

A person should work with their doctor to reassess and adjust their A1C targets over time. The condition and treatment goals may change.

To screen for diabetes, a doctor may order an A1C test for someone older than 45. They may also do this for younger people who have other risk factors.

After diagnosing diabetes, a doctor determines how often to test A1C levels.

If a person is meeting their treatment goals, they may need an A1C test twice a year. When managing blood glucose levels is challenging, a person tends to need this test more frequently.

A person should make an appointment with their doctor if they:

• have questions or concerns about their treatment plan
• are finding it hard to keep their blood glucose levels within the target range
• have had symptoms of high or low blood glucose levels
• think they might have complications of diabetes

Symptoms of high blood glucose levels include:

• fatigue
• unusual thirst
• frequent urination
• blurred vision

Symptoms of low blood glucose levels include:

• nervousness, irritability, or anxiety
• confusion
• dizziness
• hunger
• shaking
• sweating

Anyone who develops any of the symptoms above or notices other changes in their health should let their doctor know.

A doctor orders an A1C test to check whether someone has prediabetes or type 1 or 2 diabetes. Doctors also use this test to monitor blood glucose levels in people with diabetes to see how well their treatment plan is working.

A1C test results are usually a percentage, but they may come as an eAG measurement. Target A1C levels vary from person to person, depending on age, overall health, and other factors.

Having high A1C levels may indicate that the person has diabetes or a high risk of related complications. In this case, the doctor will work with the person to adjust the approach to treatment.

What is the normal AC1 level?

Normal A1C test results for people without diabetes typically range from 4.5 to 6.0 percent. For people previously diagnosed with the condition, a goal of less than 7 percent is ideal, according to the Mayo Clinic.

Although scores of 5.7 to 6.4 percent are considered prediabetes, according to the Mayo Clinic, a score of 6. 5 or higher on two separate tests is often required for diagnosis.

A1C test results may be falsely low in patients who have recently had major bleeding or a blood transfusion, while a lack of iron in the bloodstream may lead to falsely high readings. Test results in people with an unusual form of hemoglobin in their blood may be falsely high or low.

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Hemoglobin A1c levels greater than 7 percent indicate uncontrolled diabetes, which is associated with complications from the disease, according to the Mayo Clinic. The higher a patient’s A1c level, the more likely they are to experience diabetic complications. . Complications of diabetes include blindness and lower limb amputation, according to the International Diabetes Federation.

According to the Mayo Clinic, normal hemoglobin A1c levels are 4.5 to 6 percent, with higher levels indicating prediabetes or diabetes. Hemoglobin A1c indicates months of blood sugar control, and a higher percentage of hemoglobin A1c is associated with higher average blood sugar, according to WebMD. An A1c level of 8 percent indicates long-term uncontrolled diabetes, says the Mayo Clinic.

Uncontrolled diabetes contributes to cardiovascular disease, the leading cause of death in diabetics, says the International Diabetes Federation. Persistently high blood glucose, indicated by high levels of A1c, is a risk factor that increases the chance of developing diabetes, the risk of cardiovascular complications such as stroke and coronary heart disease.