Hemoglobin A1c

What Is Hemoglobin A1c?

Hemoglobin is the protein in red blood cells that carries oxygen. Sugar (glucose) naturally attaches itself to hemoglobin. The more sugar that’s in the bloodstream, the more that sticks to the hemoglobin.


Since red blood cells live for about 3 months, the Hemoglobin A1c test gives an average of the blood sugar levels over the past 2–3 months.


Think of it like a report card for blood sugar—not just a snapshot of one moment (like a fingerstick glucose check), but a bigger picture of how blood sugar has been doing over time.

Why Is the A1c Test Important?

  • For diagnosis: Doctors use HbA1c to help diagnose prediabetes and diabetes.


  • For monitoring: In those who already have diabetes, the test helps track how well their treatment plan (diet, exercise, insulin, or other medicines) is working.



  • For prevention: If a person is at risk—due to family history, weight, or other health concerns—the test can help identify changes before symptoms start.

What Do the Numbers Mean?

Results are reported as a percentage:


  • Below 5.7% – Normal


  • 5.7% to 6.4% – Prediabetes (higher than normal blood sugar, but not diabetes yet)


  • 6.5% or higher – Diabetes


For those with diabetes, doctors often set individualized A1c goals depending on age, other health issues, and risk of low blood sugar. Many guidelines aim for around 7% or less, but the “right number” can vary.

How Is the Test Done?

  • Simple blood test: It can be done with a finger stick or from blood drawn at the lab.



  • No fasting needed: Unlike some tests, it is not necessary to avoid food before this one unless other labs ordered at the time require fasting.

What Parents Should Know

  • It’s an average, not the whole story. A1c doesn’t show day-to-day ups and downs. Individuals may have low or high swings that don’t show up in the average. That’s why fingerstick checks or continuous glucose monitoring (CGM) are still important in people with diabetes.


  • Some conditions can affect results. If anemia, sickle cell trait, or other blood disorders are also present, the A1c might not be accurate. In those cases, doctors may use other tests (like fructosamine) to check average blood sugars.



  • Lifestyle matters. Healthy eating, daily activity, sleep, and stress management all play a role in keeping A1c in a healthy range.

Key Takeaway

Hemoglobin A1c is a powerful tool for understanding long-term blood sugar patterns. It helps doctors diagnose, monitor, and guide treatment for diabetes or prediabetes. Knowing what the numbers mean can make you a stronger partner in the health journey.



If you ever have questions about A1c results, don’t hesitate to ask the person who ordered the test. This may be an endocrinologist or a pediatrician or nurse practitioner in our clinic. They can explain what the results mean and what steps, if any, should be taken next.