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Hemoglobin A1c (HbA1c) by High-Performance Liquid Chromatography (HPLC)

Published: August 9, 2026Updated: August 17, 2026

This test measures the percentage of hemoglobin that is coated with sugar, reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

["HbA1c helps doctors assess long-term blood sugar control, especially important for managing diabetes."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
104679-6
Short code
DMA 18:1 RBC-mCnc
Synonyms
DMA 18:1 RBC-mCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
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 (including type 2 diabetes) and monitor how well your blood sugar is controlled over time. It’s a key tool for determining if your treatment plan is effective and adjusting medications if needed.

How Is HbA1c Different from Daily Blood Sugar Checks?

Unlike daily fingerstick blood sugar tests, HbA1c gives a broader picture by averaging your blood sugar levels over months. It’s less affected by short-term fluctuations (like stress or meals) and provides a more stable measure of long-term health.

How Is This Test Performed?

A small blood sample is taken from your arm, usually during a routine visit. The sample is processed using HPLC to separate hemoglobin types and measure the percentage of HbA1c.

What Does an HbA1c Result Mean?

Results are typically reported as a percentage (e.g., 5.7%–6.4% is considered prediabetes; 6.5% or higher may indicate diabetes). Your doctor will interpret results in the context of your overall health and treatment plan.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

Why might my doctor order an HbA1c test?
Your doctor may recommend an HbA1c test if you have symptoms of diabetes (e.g., frequent urination, extreme thirst, fatigue), a family history of diabetes, or if you’re at risk due to age, obesity, or high blood pressure. It’s also used to track diabetes progression or treatment effectiveness.
How often should I get an HbA1c test?
For people without diabetes, HbA1c testing is often recommended every 1–2 years. If you have diabetes, your doctor may check it every 3–6 months to adjust your treatment. Follow your healthcare provider’s specific schedule.
Can lifestyle changes affect HbA1c results?
Yes! Improving diet, exercise, and managing stress can lower HbA1c levels. Conversely, poor diet, lack of activity, or conditions like kidney disease may raise it. Work with your doctor to identify changes that fit your lifestyle.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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