The HbA1c value (glycated hemoglobin) is an important laboratory parameter that shows the average blood sugar level over the last 2 to 3 months. It is caused by the attachment of glucose to the hemoglobin in the red blood cells.
Meaning of the HbA1c value
In contrast to individual blood sugar measurements, the HbA1c value provides information about long-term blood sugar control. It is primarily used to assess the quality of therapy for diabetes mellitus.
Measurement and evaluation
The determination is made from a blood sample. The result is given in percent (%) or in mmol/mol. The higher the value, the higher the average blood sugar level was in the past few months.
Target values
| patient group | Target HbA1c (in%) | Target HbA1c (in mmol/mol) |
|---|---|---|
| Adults not at high risk of hypo | below 7.0% | below 53 mmol/mol |
| Elderly patients or at hypo-risk | below 7.5–8.0% | below 58-64 mmol/mol |
| Pregnant women with gestational diabetes | less than 6.5% | below 48 mmol/mol |
Influencing factors
The HbA1c value can be influenced by various factors, for example:
- Lifespan of red blood cells (e.g. in anemia)
- pregnancy
- Certain medications
- Kidney or liver disease
Further information:
→ Diabetes mellitus – knowledge and overview
→ Why hyporest
→ Type 2 diabetes
Sources
- German Diabetes Society (DDG). S3 guideline “Diabetes mellitus type 1 and type 2”. As of 2025. Available at: www.deutsche-diabetes-gesellschaft.de/leitlinien.
- American Diabetes Association. Standards of Medical Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1). Available at: diabetesjournals.org.
- Robert Koch Institute (RKI). Federal health reporting – diabetes mellitus in Germany. Berlin 2024.
- International Diabetes Federation (IDF). IDF Diabetes Atlas. 11th edition. Brussels 2025. Available at: diabetesatlas.org.
Important note:
The information in this encyclopedia article is intended solely for general and non-binding information. They do not replace medical advice, diagnosis or therapy. If you have any health questions or complaints, please always consult a doctor or qualified healthcare professional. The content was created with the greatest possible care, but errors cannot be completely ruled out.
