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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 diabetes management and long-term blood sugar control."]

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

Key facts at a glance

LOINC
77943-9
Short code
S man+haem+interc Titr Ser HA
Synonyms
S man+haem+interc Titr Ser HA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ha
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

Why is this test done?

Your healthcare provider may order an HbA1c test to diagnose diabetes, monitor existing diabetes, or check for prediabetes. It’s especially useful for people with symptoms like frequent urination, excessive thirst, or unexplained weight changes.

How is the test performed?

A small blood sample is taken from your arm, usually during a routine visit. The sample is sent to a lab where it’s analyzed using high-performance liquid chromatography (HPLC) to measure the glycated hemoglobin levels.

What does the result mean?

Results are reported as a percentage (e.g., 5.7%, 6.5%, or 7.0%). While specific ranges vary by lab, higher percentages generally indicate poorer blood sugar control. Your provider will interpret results in the context of your overall health.

Common reasons for abnormal results

Elevated HbA1c may signal uncontrolled diabetes, while lower levels could suggest recent blood sugar fluctuations or certain medical conditions. Always discuss results with your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

What causes HbA1c levels to change?
Factors like diet, exercise, medications (e.g., insulin), and underlying health conditions (e.g., kidney disease) can affect HbA1c levels. Stress, illness, or recent blood sugar spikes may temporarily alter results.
How often should I get this test?
Your doctor will determine frequency based on your diabetes status. People with type 1 diabetes may need tests every 2–3 months, while those with type 2 diabetes might check annually unless their blood sugar is unstable.
Can lifestyle changes impact HbA1c results?
Yes! Improving diet, increasing physical activity, and managing stress can lower HbA1c levels over time. Consistent lifestyle changes often lead to better long-term 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