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Glycosylated hemoglobin A3 (HbA₃) by electrophoresis

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

This test measures a form of hemoglobin that reflects long-term blood sugar levels, specifically the percentage of glycosylated hemoglobin A₃ in your red blood cells.

Quick summary

["Helps assess average blood sugar control over months."]

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

Key facts at a glance

LOINC
16932-6
Short code
Hgb A3 MFr Bld Elph
Synonyms
Hgb A3 MFr Bld Elph
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
12
Ref high
17.5
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
electrophoresis
CPT
85018
SNOMED
900000000000003004
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 This Test Might Be Ordered

Your healthcare provider may recommend this test if you have diabetes or prediabetes, or if you’re evaluating how well your blood sugar is being managed over time. It can also be useful for monitoring chronic conditions like diabetes that require long-term blood sugar tracking.

How the Test Works

Blood is drawn and processed to separate red blood cells. The hemoglobin inside these cells is then analyzed using electrophoresis, a method that separates different types of hemoglobin based on their electrical charge. The percentage of HbA₃ is determined from this separation.

What to Expect Before the Test

No special preparation is needed for this test. You may have a standard blood draw, similar to other routine lab tests. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results provide a snapshot of your average blood sugar levels over the past 2–3 months, reflecting how well your body has managed glucose levels during that time. Higher levels may indicate poorer control, while lower levels suggest better management.

Reference range

Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A

Specimen: whole-blood

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.

Clinical Significance

Short name

HbA₃

Frequently asked questions

What does a high HbA₃ level mean?
A high HbA₃ level may suggest that your blood sugar levels have been consistently higher than recommended over time, which could indicate poor diabetes management or underlying metabolic issues. It’s important to discuss these results with your healthcare provider to adjust treatment plans if needed.
What does a low HbA₃ level mean?
A low HbA₃ level may indicate that your blood sugar levels have been generally well-controlled. However, this test alone shouldn’t replace regular monitoring with other methods like fasting blood glucose or HbA₁c. Always work with your provider to interpret results in the context of your overall health.
Can HbA₃ replace HbA₁c?
HbA₃ is related to HbA₁c but provides a slightly different perspective, especially in certain populations like those with certain hemoglobin variants. HbA₁c remains the gold standard for most diabetes monitoring, but HbA₃ can offer additional insights in specific clinical scenarios. Your provider will determine the best approach for you.
  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