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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 to 3 months by examining the percentage of hemoglobin molecules that have sugar attached to them.

Quick summary

["Helps track long-term blood sugar control for diabetes management."]

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

Key facts at a glance

LOINC
44831-6
Short code
HCV c100p+5-1-1 Ab Ser Ql
Synonyms
HCV c100p+5-1-1 Ab 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
86803
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

What Is HbA1c Used For?

HbA1c is primarily used to diagnose diabetes and assess how well your blood sugar is being controlled over time. Unlike a single blood sugar test, HbA1c gives a clearer picture of your average glucose levels, which is especially useful for people with diabetes or those at risk of developing it.

How Is HbA1c Different from Other Blood Sugar Tests?

Unlike fasting or random blood sugar tests, which show your blood sugar level at a single moment, HbA1c reflects your average blood sugar over the past few months. This makes it a valuable tool for long-term monitoring and adjusting treatment plans.

Why Is HbA1c Important for People with Diabetes?

For people with diabetes, maintaining good HbA1c levels helps prevent complications like nerve damage, kidney disease, and vision problems. Regular monitoring helps healthcare providers make informed decisions about medication and lifestyle changes.

How Often Should HbA1c Be Checked?

Healthcare providers typically recommend checking HbA1c every 3 to 6 months for people with diabetes. Frequency may vary based on your overall health, treatment plan, and how well your blood sugar is controlled.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

What Does an HbA1c Test Tell Me About My Health?
An HbA1c test provides a snapshot of your average blood sugar levels over the past few months. It helps your healthcare provider determine if your diabetes treatment is effective and whether you need adjustments to your plan.
Can HbA1c Levels Change Without Me Knowing?
Yes, HbA1c levels can change gradually over time due to lifestyle factors like diet, exercise, and medication. If you notice symptoms like frequent urination, excessive thirst, or unexplained weight changes, it may be worth discussing your HbA1c levels with your doctor.
What Are Some Common Causes of High or Low HbA1c Levels?
High HbA1c levels are often linked to poor blood sugar control, diet, lack of exercise, or certain medical conditions like kidney disease. Low HbA1c levels are less common but may occur with certain medications, hormonal imbalances, or severe illness. Always consult your healthcare provider for personalized reasons.
  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