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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 levels over the past 2–3 months, helping doctors assess long-term diabetes control.

Quick summary

["HbA1c reflects your blood sugar management over time."]

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

Key facts at a glance

LOINC
32018-4
Short code
HAV IgG Ser Ql
Synonyms
HAV IgG Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 HbA1c important?

HbA1c provides a snapshot of how well your blood sugar has been controlled over time, regardless of daily fluctuations. Unlike daily blood sugar checks, it gives a clearer picture of chronic management.

How is HbA1c tested?

This test uses a small blood sample collected from your arm. The blood is processed through a specialized HPLC machine to measure the percentage of hemoglobin molecules that are attached to glucose.

What does an HbA1c result mean?

Results are typically reported as a percentage. While exact reference ranges vary by lab, higher percentages generally indicate poorer long-term blood sugar control, which can increase risks for diabetes-related complications.

Who might need an HbA1c test?

Doctors often recommend HbA1c testing for people with diabetes, those at risk for diabetes, or those with symptoms like frequent urination, excessive thirst, or unexplained weight changes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

Why do I need an HbA1c test if I don’t have diabetes?
Even if you don’t have diabetes, regular HbA1c checks can help detect prediabetes or early diabetes. It’s also useful for monitoring blood sugar levels in people with conditions like kidney disease or heart disease that may affect blood sugar.
How often should I get an HbA1c test?
The frequency depends on your health status. People with diabetes typically get tested every 2–4 months, while others may need it less often. Your healthcare provider will determine the best schedule for you.
Can diet or exercise affect my HbA1c test results?
While diet and exercise influence blood sugar levels, they don’t directly affect HbA1c. However, they can help improve your overall blood sugar control, which may indirectly benefit your test results over time.
  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