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Hemoglobin A1c (HbA1c) with mass concentration measurement by immunoassay

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 track long-term diabetes control and glucose metabolism."]

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

Key facts at a glance

LOINC
100791-3
Short code
Hmtr Epith IgG-mCnc
Synonyms
Hmtr Epith IgG-mCnc
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 This Test Measures

HbA1c reflects the amount of sugar (glucose) attached to hemoglobin in red blood cells. It’s a key indicator of how well your blood sugar has been managed over time, especially useful for diagnosing and managing diabetes.

How It’s Used in Healthcare

Doctors use HbA1c to assess whether your diabetes is well-controlled. A consistently high HbA1c may signal poor blood sugar management, while lower levels may indicate better control.

Why It Matters for You

Regular HbA1c testing helps prevent long-term complications like nerve damage, kidney disease, or heart disease by identifying trends in blood sugar levels.

What to Expect During the Test

A simple blood draw from your arm is all it takes. No special preparation is needed, but fasting isn’t required for this test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: HbA1c is a critical marker for diabetes management, offering a broader picture than daily blood sugar checks alone. It’s particularly valuable for patients with type 1 or type 2 diabetes, prediabetes, or gestational diabetes.

Short name

HbA1c

Frequently asked questions

Why might my HbA1c be checked regularly?
If you have diabetes, your doctor may recommend HbA1c testing every 3–6 months to monitor progress with treatments and adjust medications as needed.
What does an abnormal HbA1c result mean?
An HbA1c result above the target range (typically 7% or lower for most patients) may indicate poor blood sugar control and could prompt lifestyle or treatment changes.
Can diet or exercise affect HbA1c results?
Yes, diet, exercise, and medications can influence HbA1c levels. Small, consistent lifestyle changes may improve your 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