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Hemoglobin A1c (HbA1c) with mass concentration measurement from serum/plasma

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

This test measures the average blood sugar levels over the past 2–3 months by examining the percentage of hemoglobin molecules that have sugar molecules attached.

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
53959-3
Short code
HCG-TM SerPl-aCnc
Synonyms
HCG-TM SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
5
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84702
SNOMED
275917004
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, assess how well blood sugar is controlled over time, and guide treatment plans. It provides a snapshot of your average glucose levels, which can help prevent complications like nerve damage or kidney disease.

How Is HbA1c Different from Daily Blood Sugar Checks?

Unlike daily fingerstick glucose tests, HbA1c reflects your blood sugar trends over months. It’s less affected by short-term fluctuations (like meals or stress) and gives a clearer picture of long-term health risks.

How Is This Test Performed?

A small blood sample is drawn from your arm, and the serum or plasma is tested using an immunoassay method to measure the percentage of hemoglobin bound to sugar.

What Does an HbA1c Result Mean?

Results are typically reported as a percentage (e.g., 5.7%–6.4% may indicate prediabetes, while 6.5% or higher suggests diabetes). Your doctor will interpret results in the context of your overall health.

Reference range

Non-pregnant: <5 mIU/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

Why might my HbA1c result be higher than expected?
Several factors could influence HbA1c, including recent blood loss, certain medications (like iron supplements), or conditions like anemia. Your doctor may adjust interpretations based on your medical history.
How often should I get an HbA1c test?
For people with diabetes, HbA1c tests are usually recommended every 3–6 months. Your doctor may adjust frequency based on your blood sugar goals and overall health.
Can lifestyle changes affect my HbA1c result?
Yes! Diet, exercise, and weight management can significantly impact HbA1c levels. Small, consistent changes often lead to measurable improvements 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