Hemoglobin A1C (HbA1c) is one of the most important numbers in diabetes care. Unlike a single glucose reading, A1C tells you your average blood sugar over the past two to three months, making it the gold standard for diagnosing and monitoring diabetes.
How HbA1c Works
Glucose in your blood attaches to hemoglobin, the oxygen-carrying protein in red blood cells. Because red cells live about three months, the percentage of "sugar-coated" hemoglobin reflects your average glucose over that window. The higher your average sugar, the higher your A1C.
What the Numbers Mean
- Below 5.7% — Normal.
- 5.7% to 6.4% — Prediabetes. A warning sign and a powerful opportunity to change course with diet and activity.
- 6.5% or higher — Diabetes range (usually confirmed on a second test).
For most people already living with diabetes, a target under 7% is common, but your personal goal should be set with your doctor.
Why A1C Beats a Single Glucose Test
A fasting glucose is a snapshot; A1C is the whole movie. It isn't affected by whether you ate breakfast, and it smooths out day-to-day swings — which is why it's used to track long-term control and the risk of complications affecting the eyes, kidneys, nerves, and heart.
When A1C Can Be Misleading
Conditions that change red blood cell lifespan — such as anemia, recent blood loss, or certain hemoglobin variants (including thalassemia traits common in South Asia) — can make A1C unreliable. In these cases your doctor may rely more on direct glucose monitoring.
Improving Your A1C
Even small, consistent changes add up: balanced meals, reducing refined carbohydrates and sugary drinks, regular walking, weight management, and taking prescribed medication. Many people lower their A1C meaningfully within a few months.
Check Your Diabetes Markers Instantly
Got a lab report with HbA1c, fasting glucose, or insulin? Upload it to Lab Lens for an instant, easy-to-read explanation of your blood sugar control.