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Hemoglobin A1c (HbA1c) measured by high-performance liquid chromatography (HPLC)

Published: August 9, 2026Updated: August 16, 2026

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

Quick summary

["HbA1c helps doctors track long-term diabetes control and adjust treatment plans."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
40347-7
Short code
MT-TL1 m.3256C>T Bld/T Ql
Synonyms
MT-TL1 m.3256C>T Bld/T Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
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 This Test Matters for Diabetes Management

HbA1c is a key indicator of how well your diabetes is managed over time. Unlike daily blood sugar checks, it provides a broader picture of your blood sugar trends, helping prevent complications like nerve damage or kidney disease.

How the Test Works

Your blood sample is analyzed using HPLC, which separates hemoglobin molecules based on their sugar content. The test measures the proportion of glycated hemoglobin (HbA1c) compared to total hemoglobin.

What Normal Results Mean

While specific ranges vary by lab, HbA1c results are often categorized as follows: below 5.7% is generally considered normal; 5.7%–6.4% suggests prediabetes; and 6.5% or higher indicates diabetes.

Possible Causes of Abnormal Results

High HbA1c levels may indicate poor blood sugar control, while low levels (rare) could suggest recent rapid weight loss, anemia, or other conditions affecting red blood cell lifespan.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Monitoring Long-Term Health

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test?
Typically, people with diabetes should get an HbA1c test every 3–6 months to track progress and adjust medications. Your doctor may recommend more frequent testing if your blood sugar is unstable or if you’re pregnant.
What if my HbA1c is higher than my recent blood sugar readings?
HbA1c reflects long-term trends, so a higher result may mean your blood sugar was consistently elevated over time, even if recent readings were normal. This helps doctors identify patterns and adjust treatment.
Can diet or exercise affect my HbA1c results?
Yes! Improving diet, increasing physical activity, and managing medications can lower HbA1c over time. Small, consistent lifestyle changes often lead to measurable improvements in long-term blood sugar control.
  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 16, 2026. · Read our editorial policy