HbA1c — Glycated Hemoglobin
HbA1c (glycated hemoglobin) reflects the average blood glucose level over the past 2–3 months. It forms when glucose irreversibly binds to hemoglobin. This is the gold standard for assessing diabetes control.
Disclaimer. This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider for interpretation of test results.
Normal Ranges
| Value (%) | Interpretation |
|---|---|
| < 5.7 | Normal |
| 5.7–6.4 | Prediabetes (impaired glucose tolerance) |
| ≥ 6.5 | Diabetes mellitus (confirmation required) |
Target Values in Diabetes
| Category | Target HbA1c |
|---|---|
| Most adults with diabetes | < 7.0% |
| Elderly, severe comorbidities | < 8.0% |
| Pregnancy planning | < 6.5% |
Advantages Over Fasting Glucose
- Not affected by food intake — can be tested at any time
- Reflects long-term control, not a single moment
- Less influenced by acute stress or illness
Limitations
- Inaccurate with anemias, hemoglobinopathies (sickle cell, thalassemia)
- Falsely low with chronic hemolysis, significant blood loss
- Falsely high with iron deficiency anemia, splenectomy
Related Biomarkers
- Fasting Glucose — basic screening test
- Hemoglobin — anemia affects HbA1c accuracy
- Ferritin — iron deficiency may falsely elevate HbA1c
Monitoring and Trends
HbA1c should be tested every 3 months for diabetic patients and annually for routine screening. Tracking HbA1c trends is the cornerstone of diabetes management. Health Vault automatically visualizes HbA1c trends alongside related biomarkers.
FAQ
Do I need to fast for HbA1c? No, food does not affect the result. The test can be done at any time of day.
How is HbA1c different from blood sugar? Glucose shows the sugar level at one point in time. HbA1c shows the average over 2–3 months. Both tests complement each other.
What should I do if HbA1c is elevated? At 5.7–6.4% — improve diet, increase physical activity, manage weight. At ≥ 6.5% — consult an endocrinologist.
Last updated: June 2026