Hemoglobin A1c (HbA1c) measured by high-performance liquid chromatography (HPLC)
This test measures the percentage of hemoglobin that is coated with sugar, reflecting your average blood sugar levels over the past 2–3 months.
["HbA1c helps track long-term blood sugar control for diabetes management."]
Key facts at a glance
- LOINC
- 30352-9
- Short code
- Hgb BldC-mCnc
- Synonyms
- Hgb BldC-mCnc
- Category
- hematology
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 12
- Ref high
- 17.5
- Critical range
- 7 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85018
- SNOMED
- 900000000000003004
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What Does HbA1c Measure?
HbA1c reflects how your blood sugar levels have been over time. Hemoglobin is the protein in red blood cells that carries oxygen; when blood sugar binds to hemoglobin, it forms glycosylated hemoglobin (HbA1c). This test quantifies the proportion of hemoglobin that has been glycosylated, providing insight into your average glucose levels during the lifespan of red blood cells (about 3 months).
Why Is HbA1c Important?
HbA1c is a key tool for diagnosing diabetes and monitoring treatment effectiveness. It’s less affected by short-term fluctuations in blood sugar compared to immediate glucose measurements, making it a reliable indicator of long-term health.
How Is HbA1c Tested?
This test uses high-performance liquid chromatography (HPLC) to separate and measure the different types of hemoglobin in your blood sample. A small blood draw from your arm is processed to detect the percentage of HbA1c present.
What Are Common HbA1c Values?
While specific ranges vary by lab, HbA1c values are often categorized as follows (though exact ranges may differ): Normal (<5.7%), Prediabetes (5.7%–6.4%), Diabetes (≥6.5%).
Reference range
Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
HbA1c
Frequently asked questions
How often should I get an HbA1c test?
Can HbA1c be affected by other factors?
If your HbA1c is high, work closely with your healthcare team to adjust diet, exercise, or medication as needed. Small, sustainable changes can improve long-term blood sugar control and overall health.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy