HbA1c Test: What Your A1c Result Means

Hemoglobin A1c, or HbA1c, measures the percentage of hemoglobin in your red blood cells that has glucose attached to it. Because red blood cells live about 2–3 months, A1c gives a longer-term view of blood sugar than a single fasting glucose reading.

It is the standard test for diagnosing and monitoring prediabetes and diabetes. It is less affected by what you ate this morning or a poor night's sleep.

Higher A1c levels are linked to a greater risk of diabetes-related complications, including nerve, kidney, and eye damage. Lowering A1c through diet, movement, sleep, and medication when needed can reduce that risk.

A1c is not perfect. Conditions that affect red blood cells, such as anemia, recent blood loss, or certain hemoglobin disorders, can make A1c less reliable.

Blood sugar comes from carbohydrates in food and from the liver's own glucose production. There is no dietary source of A1c itself; it is a marker of how much glucose has been in your blood over time.

Foods that help stabilize blood sugar include non-starchy vegetables, legumes, whole grains, nuts, seeds, lean proteins, and healthy fats. Limiting sugary drinks and refined carbohydrates often has the biggest impact.

Diet, body weight, physical activity, sleep, stress, alcohol, medications such as steroids, and conditions affecting red blood cells can all influence A1c. Pregnancy uses different glucose targets and screening tests.