what is the definition of a1c

The A1C test, also known as the hemoglobin A1C or HbA1c test, is a blood test that measures your average blood sugar levels over the past 2 to 3 months. It works by measuring the percentage of your red blood cells that have sugar-coated hemoglobin. Hemoglobin is a protein in red blood cells that carries oxygen, and glucose in the blood attaches to it. The higher your blood sugar levels, the more glucose attaches to hemoglobin.

• Normal A1C: Below 5.7%
• Prediabetes: 5.7% to 6.4%
• Diabetes: 6.5% or above

The A1C test is commonly used to diagnose prediabetes and diabetes, as well as to monitor how well diabetes is being managed over time.