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Serum Immunoglobulin G (IgG) Subclass Analysis by Electrophoresis

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

This test measures the levels of different subclasses of Immunoglobulin G (IgG), a key antibody protein in your immune system. It helps assess how your body produces and balances these subclasses, which can be important for diagnosing or monitoring certain immune-related conditions.

Quick summary

["IgG subclasses help identify immune system function and potential deficiencies or disorders."]

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

Key facts at a glance

LOINC
55396-6
Short code
B2 glycoprot1 IgA+IgG Pnl Ser
Synonyms
B2 glycoprot1 IgA+IgG Pnl Ser
Category
glucose
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 Does This Test Measure?

The test evaluates four main IgG subclasses: IgG1, IgG2, IgG3, and IgG4. Each subclass plays a distinct role in immune defense, and their relative amounts can provide clues about immune responses, allergies, infections, or autoimmune conditions. Some subclasses are more effective at neutralizing viruses, while others help clear bacteria or fight chronic inflammation.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like frequent infections, unusual allergic reactions, chronic fatigue, or if you’re being treated for an immune disorder (e.g., lupus, rheumatoid arthritis). It can also be used to monitor immune function in people with certain genetic conditions or after receiving immune-boosting treatments.

Sample Collection and Preparation

This test uses a blood sample drawn from a vein in your arm. After drawing blood, it’s sent to a lab where it’s processed into serum (the liquid part left after blood clots). The serum is then analyzed using electrophoresis, a technique that separates proteins based on size and charge to identify IgG subclass levels.

What to Expect Before the Test

No special preparation is needed for this test. You can eat, drink, or take medications as usual on the day of your blood draw. If you’re on blood-thinning medications, let your provider know before the test to avoid unnecessary precautions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test helps diagnose or manage conditions where IgG subclass levels are abnormal, such as: • Hypogammaglobulinemia (low IgG overall or in specific subclasses) • Common variable immunodeficiency (a rare immune disorder) • Autoimmune diseases (e.g., lupus, vasculitis) • Allergic reactions or chronic infections • Monitoring immune responses post-transplant or after immune-modifying treatments. Abnormal results may indicate an immune system that’s too weak or overactive, guiding treatment decisions like antibody therapy or lifestyle adjustments.

Short name

IgG Subclass Profile (Serum)

Frequently asked questions

How long does it take to get my results?
Results from this test typically arrive within 1–3 business days, depending on your lab’s processing schedule. Your healthcare provider will discuss the findings with you during your follow-up visit.
Can I eat or drink anything before this test?
Yes, you can eat and drink normally before your blood draw. Avoid fasting unless instructed by your provider, as it may affect other tests you’re scheduled for.
Will I feel any pain or discomfort during the blood draw?
Most people experience only mild discomfort during the blood draw, like a slight pinch when the needle is inserted. The area may feel tender afterward, but this usually goes away quickly. Tell your provider if you’re worried about needles or have a history of severe reactions.
  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