When it comes to testing for diabetes, you may be familiar with the glucose test, which is often a standard part of lab work at your annual checkup. But there’s another test you should get to know: the A1C test.
This test is a tool used to get a good look at your blood sugar. It is used to diagnose prediabetes and diabetes and is a helpful guide for managing diabetes after diagnosis.
What is the test and why would you need it? Dr. Alberto Chavez-Velazquez, a University Health endocrinologist, answers some frequently asked questions about the A1C test below.
What Is a Hemoglobin A1C (HbA1C) Test?
An HbA1C test, more commonly called an A1C test, is a blood test that shows an average blood glucose level over a 2- to 3-month period.
Hemoglobin is a protein in your red blood cells that’s responsible for carrying oxygen to body tissue. Glucose, or blood sugar, sticks to hemoglobin. The A1C test gauges your blood sugar by measuring the amount of hemoglobin with glucose attached to it.
This test offers benefits over a standard glucose test when it comes to detecting diabetes. For one, you do not need to fast before an A1C test because it measures blood sugar over a longer period.
Who Needs an A1C Test?
Those who are age 45 or older should have an A1C test at least every 3 years if results are normal. Dr. Chavez-Velazquez says, if the test shows prediabetes, repeat testing may be recommended every 1 to 2 years.
People at Risk of Diabetes
Those who are younger than age 45 should have an A1C test if they’re at an increased risk of diabetes due to:
- Having prediabetes
- Being overweight or obese
- Having a family history of Type 2 diabetes
- Having other risk factors
People with Symptoms of Diabetes
A1C testing is also recommended for anyone experiencing symptoms of diabetes, such as:
- Extreme thirst
- Increased urination
- Weight loss with no known cause
- Non-healing wounds
Learn more about our world-class diabetes care at the Texas Diabetes Institute.
Is the A1C Test Right for You?
“Talk with your provider about whether A1C testing is right for you,” says Dr. Chavez-Velazquez.
The test is highly accurate, but false results can occur for those with iron-deficiency anemia, kidney failure, liver disease or a blood-related disorder such as sickle cell anemia or thalassemia.
What Should I Expect from an A1C Test?
An A1C test is a simple blood test requiring only a few minutes of your time.
Before the A1C Test
Many people wonder, “Do you have to fast before an A1C test?” The answer is no. No fasting or other advance preparation is required prior to testing.
During the A1C Test
During an A1C test, a medical provider will take a small blood sample from a vein in your arm. This process is relatively painless, though you may feel some discomfort or stinging when the needle enters and exits your arm.
After the A1C Test
After the blood sample is drawn, your part of the process is done! You can now wait on the results from your provider.
Risks of an A1C Test
There is very little risk associated with an A1C test, which requires only a small blood sample. In some cases, you may experience a little bleeding or bruising on your arm where the needle was inserted.
How to Read A1C Test Results
The A1C test measures the amount of hemoglobin in your blood that’s coated in blood glucose. Test results are indicated in a percentage — which is the percentage of hemoglobin bonded with glucose.
Normal: Below 5.7%
Prediabetes: Between 5.7-6.4%
Diabetes: 6.5% or higher
Your provider may use additional testing to confirm the diagnosis and may have you repeat an A1C test in a few months. Other tests include a fasting blood glucose test or an oral glucose tolerance test.
Where Can I Get an A1C Test?
Body You can have an A1C test performed at:
- Your primary care provider’s office
- An urgent care facility
- A hospital
- A specialist’s office
In any of those medical settings, you can trust the results to be highly accurate.
Once your blood sample is drawn in a medical office, it will be sent to a lab that uses an NGSP-certified method to analyze the sample. The NGSP certifies that the makers of A1C tests provide results that are consistent and comparable with what was used in clinical trials.
Is an At-Home A1C Test Accurate?
In recent years, several manufacturers have created at-home tests. But how accurate is an A1C home test?
According to Dr. Chavez-Velasquez, at-home A1C tests’ accuracy and reliability can vary. “These A1C tests generally provide results that are close to those obtained in a clinical or laboratory setting. However, factors such as improper sample collection, storage and handling can affect accuracy,” Dr. Chavez says. Because of this, they can’t be used to diagnose diabetes.
Plus, while some A1C tests are FDA-approved and have undergone validation studies, they may not be as reliable as a test performed in a laboratory. Variability in results can occur due to differences in test quality and user technique.
“In my opinion, kits for home use could be useful for occasional monitoring or to see trends in between doctor visits, but they should not replace periodic testing by a health care professional,” Dr. Chavez says. “Because there are many factors that can affect A1C results and interpretation, it’s always best to discuss results with your doctor.”
Diabetes Care at University Health
Diabetes can have long-term effects on your body. But with early detection and lifestyle changes, you can protect and take control of your health.
If you are at risk of diabetes, schedule an appointment with your primary care provider and ask for an A1C test.
Community Resources
Whether you receive care from us or not, you can find community resources related to diabetes care through our Institute for Public Health.
Diabetes is a long-lasting health condition — left unmanaged could lead to other health complications.
Our free online risk assessment only takes a few minutes. It will help you better understand your risk of developing Type 2 diabetes and how you may be able to lower it.
