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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 average blood sugar (glucose) levels over the past 2 to 3 months, helping doctors assess long-term control of diabetes.

Quick summary

["HbA1c reflects your blood sugar control over time, a key measure for diabetes management."]

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

Key facts at a glance

LOINC
14507-8
Short code
C trach Ag Bld Ql IF
Synonyms
C trach Ag Bld Ql IF
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 HbA1c Tests Measure

HbA1c is a form of hemoglobin (the oxygen-carrying protein in red blood cells) that has attached glucose molecules over time. It reflects your blood sugar levels during the production of red blood cells, which live for about 3 months. This test is a reliable indicator of how well your diabetes is controlled over time, rather than just a single blood sugar reading.

Why It’s Done

Doctors order HbA1c tests to monitor diabetes management, diagnose prediabetes, or evaluate long-term blood sugar control. It’s particularly useful for people with type 1 or type 2 diabetes, as it provides a broader picture than daily blood sugar checks alone.

How It’s Performed

A small blood sample is taken from your arm, usually by a healthcare professional. The sample is then analyzed using high-performance liquid chromatography (HPLC), which separates hemoglobin variants based on their glucose attachment to measure HbA1c levels accurately.

What the Results Mean

Results are typically reported as a percentage. While exact reference ranges vary by lab, higher percentages generally indicate poorer blood sugar control. For example, a result of 6.5% or higher may suggest diabetes, while lower values may indicate better control.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test?
If you have diabetes, your doctor may recommend testing every 3 to 6 months to track progress with your treatment plan. For prediabetes, testing may be less frequent, but regular check-ups are still important to prevent diabetes from developing.
Can lifestyle changes affect HbA1c results?
Yes, diet, exercise, and managing stress can improve HbA1c levels. Small, consistent changes—like eating balanced meals, staying active, and avoiding smoking—can help lower your HbA1c over time.
What does an abnormal HbA1c result mean?
An abnormal result may signal poor blood sugar control and could prompt adjustments to your diabetes treatment, such as medication changes or dietary recommendations. Always discuss results with your healthcare provider for personalized advice.
  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