Hemoglobin A1c (HbA1c) measured by high-performance liquid chromatography (HPLC)
This test measures the average blood sugar levels over the past 2–3 months by examining the percentage of hemoglobin that is coated with sugar. It helps doctors assess long-term diabetes control.
["HbA1c reflects your blood sugar trends over time, aiding diabetes management."]
Key facts at a glance
- LOINC
- 53958-5
- Short code
- HCG-TM SerPl-sCnc
- Synonyms
- HCG-TM SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 5
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84702
- SNOMED
- 275917004
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What HbA1c Tests Measure: An HbA1c test measures your average blood sugar levels over the past two to three months by showing the percentage of hemoglobin in your red blood cells that has glucose attached to it.
HbA1c tests specifically look at the proportion of hemoglobin molecules that have sugar molecules attached. Hemoglobin is the protein in red blood cells that carries oxygen. Over time, high blood sugar can bind to hemoglobin, forming HbA1c. This test quantifies that binding to gauge how consistently your blood sugar has been elevated.
Why This Test Matters: This test matters because it helps diagnose prediabetes and diabetes, shows how well your current treatment plan is working, and can identify your long-term risk for complications affecting your heart, kidneys, nerves, and eyes.
Unlike daily blood sugar checks, HbA1c provides a broader picture of your glucose management. It’s particularly useful for diagnosing diabetes, monitoring treatment effectiveness, and detecting early signs of poor control.
How the Test Works: When glucose builds up in your bloodstream, it naturally binds to hemoglobin, the oxygen-carrying protein inside red blood cells. Because red blood cells live for about three months, measuring this bound glucose gives a reliable picture of your average levels over time.
Blood is drawn and separated into its components. The hemoglobin fraction is analyzed using HPLC, which separates and measures the percentage of HbA1c relative to total hemoglobin. This method is precise and avoids interference from recent blood sugar spikes.
Sample Preparation and Collection: No fasting is required for an HbA1c test, so you can eat and drink normally before your appointment. A healthcare professional will draw a small blood sample from a vein in your arm, though a fingerstick sample may be used in some settings.
A simple blood draw from your arm is all that’s needed. No special preparation is required, but fasting is not necessary. The test uses a small sample of whole blood, which is processed to isolate hemoglobin for analysis.
Reference range
Non-pregnant: <5 mIU/mLN/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
Short name
HbA1c
Frequently asked questions
HbA1c is a cornerstone of diabetes care, offering a reliable, objective measure of glycemic control. It helps identify whether your treatment plan is working, adjusts medications, and reduces the risk of long-term complications like nerve damage, kidney disease, or heart disease. Abnormal results may prompt further investigation or treatment adjustments.
Typically, people with diabetes get an HbA1c test every 3–6 months to track progress. Your doctor may recommend more frequent testing if your blood sugar is unstable or if you’re adjusting medications. Regular monitoring helps catch issues early and keeps your treatment plan on track.
Results are usually reported as a percentage (e.g., 5.7%, 6.5%, 7.0%). A result below 5.7% is generally considered normal, while 5.7%–6.4% may indicate prediabetes. A result of 6.5% or higher suggests diabetes. Your doctor will interpret results in the context of your overall health and treatment goals.
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