Medically reviewed by Rosanna Sutherby, PharmD on March 31, 2021. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
While diabetes is most often associated with blood sugar and glucose meters, one of the most important markers for assessing diabetes risk and monitoring diabetes is one’s HbA1c number (which can be measured by an HbA1c test). So what is HbA1c, and what is a normal A1c level? Read on to learn more.
Related: How many people have diabetes?
Blood sugar, also known as glucose, is your body’s main and most easily accessible source of energy. When you eat food, it gets broken down into its most basic components and enters your bloodstream. Your blood then transports the sugar to all the cells within your body for energy, using the help of a hormone called insulin.
HbA1c, or hemoglobin A1c, refers to glycated hemoglobin. Hemoglobin is the main protein in red blood cells that is responsible for carrying oxygen from the lungs to the rest of the body. As sugar circulates in your bloodstream, some sugar molecules stick to the hemoglobin in one’s red blood cells—so the hemoglobin is considered glycated. These sugar molecules stay there for the rest of the red blood cell’s lifespan, which is usually about 3 months (your body keeps making new red blood cells as old ones die off). If there’s a lot of sugar in your bloodstream, then a lot of your red blood cells will be covered with sugar molecules.
A1c tests (or HbA1c tests) use the glycated hemoglobin in a sample of blood to determine a person’s HbA1c number—an indicator of the average blood sugar level over the past 3 months.
While both HbA1c tests and glucose meters use a blood sample to report results, an HbA1c test is not the same as the glucose result you get from a blood glucometer (or “glucose meter”).
A glucometer determines your at-the-moment blood sugar level (commonly in milligrams per deciliter, or mg/dL), which often swings up and down throughout the day as you eat and exercise. On the other hand, an HbA1c test measures the percentage of the hemoglobin in your red blood cells that’s covered in sugar (or glycated)—giving you a good idea of your average blood sugar level over the past 3 months.
Because an HbA1c test shows your average blood sugar level over the past 3 months, it’s a reliable and consistent way to monitor long-term changes in blood sugar. It’s also a common test used by healthcare professionals to diagnose diabetes. However, this test is not a replacement for regular blood glucose monitoring in diabetic patients.
As mentioned above, HbA1c test results are represented as a percentage. A higher HbA1c percent corresponds to a higher 3-month average blood sugar level, and if one’s HbA1c number is above the normal range, they may be at a greater risk of developing diabetes.
So what is a normal A1c level? According to the American Diabetes Association, the normal HbA1c level for adults is below 5.7%. A1c levels between 5.7% and 6.4% may indicate prediabetes, while those with diabetes will often show A1c levels of 6.5% and higher. (Prediabetes refers to a blood sugar level that is above the normal range but isn’t in the diabetes range; people with prediabetes are at an increased risk of developing diabetes if preventive measures—such as lifestyle changes—are not taken.)
It’s important to call out at this point that, in reality, there isn’t a specific “normal” range for HbA1c that universally applies to everyone. An HbA1c result needs to be interpreted through the lens of the unique clinical context of a given person. That’s because there are a variety of factors—not just one’s blood sugar levels—that can potentially affect hemoglobin glycation.
For example, one’s race or ethnicity is a possible variable that can impact HbA1c levels. Research shows that people without diabetes who are from Black, Asian, or Latinx communities tend to have higher HbA1c values compared to White individuals.
Other factors that can be connected to HbA1c levels include:
With this in mind, it’s a good idea to share your HbA1c test results with your healthcare provider so they can evaluate your results in the context of other factors that may be relevant to you as a unique person.
Easily check your HbA1c—an indicator of the average sugar level in your blood over the past 3 months that’s routinely used for diabetes management—with the Everlywell at-home HbA1c Test. You’ll get secure, digital results viewable on your device within days of sending your sample to the lab, along with the option to share your results with your healthcare provider.
The Centers for Disease Control and Prevention (CDC) recommends getting a baseline HbA1c test if you are over the age of 45. The CDC also suggests A1c testing if you are younger than 45 but are considered overweight and have risk factors associated with prediabetes or type 2 diabetes [ref].
If you’ve been diagnosed with diabetes or prediabetes, it’s best to speak with your healthcare provider to determine what testing frequency they recommend for you.
More on diabetes: “Why do I have blurry vision?” Understanding what causes blurred vision
HbA1c tests are an important tool for diagnosing and managing diabetes, but it is merely one tool in a larger tool shed. Regular blood sugar testing with a glucose meter is important for tracking glucose levels throughout the day. Keeping track of your daily blood sugar levels can help you and your diabetes care team optimize your treatment plan and lifestyle so you can hit your glycemic targets.
To check your HbA1c from the convenience of home, try the Everlywell at-home hemoglobin A1c test—which comes with everything you need to easily collect a small blood sample at home and send it to a lab for testing.
1. National Diabetes Statistics Report, 2020. Centers for Disease Control and Prevention. URL. Accessed March 31, 2021.
2. Guide to HbA1c. Diabetes.co.uk. URL. Accessed March 31, 2021.
3. Test ID: HBA1C. Mayo Clinic. URL. Accessed March 31, 2021.
4. Hemoglobin A1C (HbA1c) Test. Medline Plus. URL. Accessed March 31, 2021.
5. Texas Children's Hospital. "ADA lowers target HbA1C levels for children with type-1 diabetes". ScienceDaily. URL. Accessed March 31, 2021.
6. All About Your A1C. Centers for Disease Control and Prevention . URL. Accessed March 31, 2021.
7. Kirk JK, D'Agostino RB Jr, Bell RA, et al. Disparities in HbA1c levels between African-American and non-Hispanic white adults with diabetes: a meta-analysis. Diabetes Care. 2006;29(9):2130-2136. doi:10.2337/dc05-1973
8. It’s called the A1C test, and it’s a powerhouse. American Diabetes Association. URL. Accessed March 31, 2021.
9. Cavagnolli G, Pimentel AL, Freitas PA, Gross JL, Camargo JL. Effect of ethnicity on HbA1c levels in individuals without diabetes: Systematic review and meta-analysis. PLoS One. 2017;12(2):e0171315. Published 2017 Feb 13. doi:10.1371/journal.pone.0171315
10. American Diabetes Association. 2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2020. Diabetes Care. 2020;43(Suppl 1):S14-S31. doi:10.2337/dc20-S002