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 doctors track long-term diabetes control and adjust treatment plans."]
Key facts at a glance
- LOINC
- 103135-0
- Short code
- Honey bee (rApi m) 3 IgE RAST
- Synonyms
- Honey bee (rApi m) 3 IgE RAST
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- rast
- CPT
- 84484
- SNOMED
- 302774002
- 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
HbA1c reflects your blood sugar levels over time by showing how much sugar has attached to hemoglobin, the protein in red blood cells that carries oxygen. This test is a key tool for managing diabetes and prediabetes, as it provides a snapshot of your average glucose exposure over months rather than just recent blood sugar spikes or drops.
How the Test Works
The test uses high-performance liquid chromatography (HPLC) to separate and measure hemoglobin variants, including those with attached sugar. This method is precise and widely used because it avoids interference from other blood components that could affect other testing methods.
Why It Matters for You
HbA1c is critical for diabetes management because it helps doctors assess whether your current treatment is keeping your blood sugar within healthy ranges. It also helps identify trends over time, such as whether your blood sugar is consistently too high or too low, which can inform lifestyle or medication adjustments.
Common Reasons for Testing
Your healthcare provider may order an HbA1c test if you have diabetes, prediabetes, or if you’re at risk for diabetes due to factors like obesity, family history, or physical inactivity. It’s also used during pregnancy (in some cases) to monitor gestational diabetes and regularly in people with chronic conditions like kidney disease or heart disease that may affect blood sugar control.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
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 test results change if I’ve recently eaten or exercised?
What do my HbA1c results mean if they’re outside the normal range?
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 17, 2026. · Read our editorial policy