Hemoglobin A1c (HbA1c) with mass fraction measurement by high-performance liquid chromatography (HPLC)
This test measures your average blood sugar levels over the past 2–3 months by examining the percentage of hemoglobin (the oxygen-carrying protein in red blood cells) that is attached to sugar (glycated hemoglobin). It helps doctors assess long-term blood sugar control, especially useful for managing diabetes.
["HbA1c helps track how well your blood sugar is managed over time, aiding diabetes care and prevention of complications."]
Key facts at a glance
- LOINC
- 71868-4
- Short code
- Hgb D MFr.DF Bld
- Synonyms
- Hgb D MFr.DF Bld
- 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
Why Is This Test Done?
Doctors order HbA1c tests primarily to diagnose type 1 or type 2 diabetes, monitor blood sugar levels in people with diabetes, and check for prediabetes. It’s also useful for evaluating how well diabetes treatments (like medication or diet) are working.
How Is the Test Performed?
A small blood sample is taken from your arm, usually during a routine visit to your healthcare provider. The sample is then analyzed using high-performance liquid chromatography (HPLC) to measure the percentage of glycated hemoglobin.
What Do Results Mean?
Results are reported as a percentage (e.g., 5.7%, 6.4%, 7.5%). While exact reference ranges vary by lab, higher percentages generally indicate poorer blood sugar control. For example, levels above 6.5% may suggest diabetes, while levels below 5.7% are often considered normal.
What Are Common Causes of Abnormal Results?
Abnormal HbA1c results can occur due to diabetes (high levels), non-diabetic conditions (like chronic kidney disease or certain medications), or errors in test interpretation. Low levels may sometimes indicate recent rapid blood sugar changes or certain blood disorders.
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.
Clinical Significance: HbA1c is a critical marker for diabetes management because it reflects long-term blood sugar trends. Regular monitoring helps prevent complications like nerve damage, kidney disease, or heart problems. It’s also useful for identifying prediabetes early, when lifestyle changes can slow disease progression.
Short name
HbA1c (Blood Sugar Control)
Frequently asked questions
How often should I get an HbA1c test if I have diabetes?
Can HbA1c results change if I’ve recently had a blood transfusion?
Does diet or exercise affect HbA1c test results?
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