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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, reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

["HbA1c helps doctors track diabetes control and long-term blood sugar health."]

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

Key facts at a glance

LOINC
21054-2
Short code
HAdV IgM Ser Ql
Synonyms
HAdV IgM 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

What Is HbA1c Used For?

HbA1c is primarily used to diagnose type 1 and type 2 diabetes and to monitor how well blood sugar is managed over time. It provides a snapshot of your glucose control that isn’t affected by short-term fluctuations, like stress or recent meals.

How Is HbA1c Different from Fasting Blood Sugar?

Unlike a single fasting blood sugar test, HbA1c gives a broader picture of your blood sugar trends. It doesn’t depend on when you last ate or drank, making it a reliable measure for long-term diabetes management.

Why Is HbA1c Important for People Without Diabetes?

Even if you don’t have diabetes, your doctor may check HbA1c if you have risk factors like obesity, a family history of diabetes, or high blood pressure. It helps identify prediabetes or early signs of glucose issues.

How Does HbA1c Work?

Hemoglobin in your red blood cells binds to glucose over time, forming HbA1c. The test measures this percentage, which correlates with your average blood sugar levels during the previous 2–3 months.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

HbA1c plays a critical role in diabetes care by providing a consistent, long-term measure of blood sugar control. It helps doctors adjust treatments, like medication or diet, to keep glucose levels within healthy ranges and reduce risks of complications like nerve damage or heart disease.

Short name

HbA1c

Frequently asked questions

Why might my HbA1c be higher than expected?
Several factors can affect HbA1c, including recent illness, blood loss, or certain medications. If your levels seem unusually high, discuss potential causes with your doctor.
Is HbA1c the same as a blood sugar test I can do at home?
No, home blood sugar tests measure current glucose levels, while HbA1c reflects long-term trends. Your doctor uses HbA1c to assess overall diabetes management, not just immediate readings.
Can HbA1c be affected by anemia or other blood conditions?
Yes, conditions like anemia (low red blood cells) can sometimes alter HbA1c results. If you have a blood disorder, your doctor may need to interpret the test differently or use additional tests for accuracy.
  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