Hemoglobin A1c (HbA1c) with calculated mean glucose index (calculated from glycated hemoglobin)
This test measures your average blood sugar levels over the past 2–3 months by analyzing the percentage of hemoglobin molecules that have sugar (glucose) attached. It helps doctors assess long-term blood sugar control.
["HbA1c reflects your blood sugar management over time, not just recent spikes."]
Key facts at a glance
- LOINC
- 105040-0
- Short code
- Hgb BldMV Calc-mCnc
- Synonyms
- Hgb BldMV Calc-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
- Method
- calculated
- 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 Is HbA1c Used For?
HbA1c is primarily used to diagnose diabetes, monitor long-term blood sugar control, and guide treatment plans. It’s a key indicator of how well your body manages glucose levels, especially important for people with type 1 or type 2 diabetes.
How Is HbA1c Different from Recent Blood Sugar Checks?
Unlike quick blood sugar tests (e.g., fingerstick glucose), HbA1c gives a broader picture by measuring the percentage of hemoglobin coated with sugar. This helps identify trends over time rather than just immediate readings.
How Is This Test Performed?
A small blood sample is taken from your arm, usually during a routine visit. The test measures the percentage of glycated hemoglobin in your red blood cells, which reflects average blood sugar exposure over months.
What Does an HbA1c Result Mean?
Results are typically reported as a percentage (e.g., 5.7%, 6.5%, 7.0%). Lower percentages (closer to 5.7%) suggest better blood sugar control, while higher values indicate poorer management. Exact thresholds for diabetes diagnosis vary by lab and guidelines.
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 (Glycated Hemoglobin)
Frequently asked questions
Why do doctors order this test?
How often should I get this test?
Can HbA1c be affected by other health conditions?
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