Serum Hemoglobin A1c (HbA1c) with Mass Concentration Measurement
This test measures the percentage of hemoglobin that is glycated (attached to sugar) in your red blood cells, reflecting your average blood sugar levels over the past 2–3 months.
["HbA1c helps doctors assess long-term blood sugar control for diabetes or prediabetes."]
Key facts at a glance
- LOINC
- 75928-2
- Short code
- Hgb BldA-sCnc
- Synonyms
- Hgb BldA-sCnc
- 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 This Test Measures
HbA1c reflects how well your blood sugar has been managed over time. It’s a stable marker because red blood cells live for about 3–4 months, so it integrates your blood sugar trends from that period.
Why It Matters for Your Health
High HbA1c levels may indicate poor blood sugar control, increasing risks for complications like nerve damage, kidney disease, or heart disease. Low levels might suggest consistently healthy glucose management.
How It’s Done
A small blood sample is taken from your arm, usually during a routine visit. The test measures the percentage of glycated hemoglobin in your serum (liquid part of blood).
What to Expect Before or After
No special preparation is needed, but inform your provider if you’re taking certain medications (e.g., blood thinners) or have recent blood transfusions. Results are typically ready within 24–48 hours.
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.
HbA1c is a key tool for diagnosing diabetes (typically ≥6.5%) and monitoring treatment in people with prediabetes (5.7%–6.4%) or diabetes. It’s more reliable than random blood sugar checks for long-term trends.
Short name
HbA1c
Frequently asked questions
How often should I get this test?
What do my results mean?
Can lifestyle changes affect this test?
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