Health Column
HbA1c Chart: What 5.7 and 6.5 Mean
HbA1c is the percentage of the hemoglobin in your red blood cells that has glucose attached to it. Because red blood cells live about 120 days, it reflects your average blood glucose over the past 2 to 3 months. You don't need to fast for the test, and it is less affected by changes during the day.
HbA1c ranges
| HbA1c | Category |
|---|---|
| Below 5.7% | Normal |
| 5.7 – 6.4% | Prediabetes |
| 6.5% or higher | Diagnostic criterion for diabetes |
Based on "Diabetes" from the KDCA National Health Information Portal.
It can differ from fasting glucose
Fasting glucose is the value on the morning of the test, while HbA1c is the average of the past few months. If your fasting glucose is normal but your HbA1c is in the prediabetes range, it is possible that your post-meal blood glucose has often been high. That is why the two tests are looked at together.
Control status
According to the Korean Diabetes Association 2024 Fact Sheet, only 32.4%, or 1 in 3, of people with diabetes keep their HbA1c below 6.5%.
- KDCA National Health Information Portal, "Diabetes"
- Korean Diabetes Association, Diabetes Fact Sheets in Korea 2024 (Diabetes Metab J 2025;49:24-33), based on KNHANES 2021–2022