Understanding Hemoglobin A1c
The test measures the percentage of hemoglobin with glucose attached. It helps clinicians screen for or diagnose prediabetes and diabetes and monitor glucose management. Unlike a single glucose reading, it reflects a longer period.
How it is assessed or used in care
A1c testing generally does not require fasting. Certain anemias, hemoglobin variants, pregnancy, and other conditions can affect accuracy. A clinician may use other tests or confirm an unexpected result before making a diagnosis.
What to discuss with your clinician
Ask what your result means and what target, if any, is appropriate for you. Treatment goals differ with health circumstances. A1c does not reveal every daily high or low glucose episode, so other monitoring may still be important.
Medical references
Sources accessed November 13, 2026.
This information is for general education, not a diagnosis or an individualized treatment plan. Discuss symptoms, test results, and treatment decisions with a qualified clinician. For a medical emergency, call 911.