What is HbA1c (Hemoglobin A1c)?
Also written as：Hemoglobin A1c ／ Glycohemoglobin
HbA1c represents the percentage of hemoglobin in red blood cells that has glucose attached to it. Rather than reflecting only your blood sugar at the moment of the blood draw, it captures your average blood sugar control over the past 1–2 months. Because it is not significantly affected by recent meals, it is widely used to diagnose diabetes and evaluate how well blood sugar is being managed. It is one of the standard items included in specific health checkups (tokutei kenshin).
Reference range guideline
A level of 5.5% or below is generally considered the target. In specific health checkups, a result of 5.6% or above is often used as the threshold for lifestyle guidance, and 6.5% or above typically triggers a recommendation to see a doctor (thresholds may vary by facility and year).
* Reference ranges vary by testing facility, measurement method, age, sex, and other factors. Please check the reference range printed on your result sheet.
How to interpret an out-of-range result
An elevated result may suggest an abnormality in glucose metabolism; however, a diagnosis of diabetes cannot be confirmed by HbA1c alone. A physician will make a comprehensive assessment by considering fasting blood glucose and other findings together.
Related tests and conditions
Frequently asked questions
I was told my HbA1c is high. Does that mean I have diabetes?
Related terms
Sources & references
This page provides general information only and is not intended for diagnosis or treatment. Please consult the physician at your chosen facility regarding the interpretation of your health checkup results.