Skip to content

Glycated hemoglobin (HbA₁c) measured by high-performance liquid chromatography (HPLC)

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

This test measures the percentage of hemoglobin molecules that have sugar (glucose) attached, reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

["HbA₁c helps doctors assess long-term blood sugar control for diabetes or prediabetes."]

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

Key facts at a glance

LOINC
55246-3
Short code
HBA2 c.84G>C Bld Ql
Synonyms
HBA2 c.84G>C Bld 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 is this test important?

Unlike daily blood sugar checks, HbA₁c gives a broader picture of how well your blood sugar has been managed over time. It’s a key tool for managing diabetes and preventing complications like nerve damage or kidney disease.

How is the test performed?

A small blood sample is taken from your arm. The sample is processed to separate hemoglobin types and analyzed using HPLC to determine the glycated fraction. Results are reported as a percentage of total hemoglobin.

What does the test tell you?

HbA₁c levels above or below typical ranges can indicate whether your blood sugar is consistently high or low. While exact reference ranges vary by lab, higher levels often suggest poor diabetes control, while lower levels may indicate hypoglycemia or other conditions.

What might affect your HbA₁c results?

Factors like recent blood loss, severe illness, or certain medications (e.g., some blood thinners) can temporarily alter HbA₁c levels. Smoking or pregnancy may also influence results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA₁c

Frequently asked questions

How often should I get this test?
Your doctor will determine how frequently you need HbA₁c testing based on your diabetes management plan. Typically, tests are done every 3–6 months for stable patients, but more often if your levels fluctuate.
What if my HbA₁c is higher than expected?
A higher HbA₁c may mean your blood sugar has been consistently elevated. Your doctor will review your treatment plan, including diet, exercise, and medications, to help bring levels down.
Can lifestyle changes impact my HbA₁c results?
Yes! Improving diet, increasing physical activity, and managing stress can help lower HbA₁c. Consistently monitoring and adjusting these habits may lead to better 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