Skip to content

Serum Immunoglobulin G (IgG) Subclass Analysis (Bromocresol Green or Bromocresol Purple Electrophoresis)

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

This test measures different types of Immunoglobulin G (IgG), a key antibody protein in your blood, broken down into its subclasses for detailed evaluation.

Quick summary

["Understanding your IgG subclasses can help identify immune system imbalances or specific antibody deficiencies."]

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

Key facts at a glance

LOINC
16135-6
Short code
B2 Glycoprot1 IgG Ser-aCnc
Synonyms
B2 Glycoprot1 IgG Ser-aCnc
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

Why This Test Is Done

Your doctor may order this test if you have symptoms like frequent infections, autoimmune conditions, or if you’ve been diagnosed with a condition affecting antibody production. It can also be part of a broader immune evaluation, such as for HIV, lupus, or other immune disorders.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

IgG is divided into four subclasses (IgG1, IgG2, IgG3, IgG4). Abnormal levels in any subclass may indicate immune system dysfunction, such as low antibody production or excessive immune activity. Your doctor will compare your results to standard ranges and correlate them with your symptoms.

Possible Conditions Linked to IgG Subclass Results

Low levels of certain IgG subclasses may suggest conditions like common variable immunodeficiency (CVID), where the immune system doesn’t produce enough antibodies. High levels of IgG3, for example, might be seen in certain autoimmune diseases or chronic infections. Always discuss your results with your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG subclass testing

Frequently asked questions

What causes abnormal IgG subclass levels?
Abnormal IgG subclass levels can result from genetic disorders, chronic infections, autoimmune diseases, or medications that affect antibody production. Conditions like CVID, HIV, or certain cancers can also alter IgG subclass distribution.
How often should I get this test?
Your doctor will determine how often you need this test based on your medical history, symptoms, and treatment plan. Some patients may need follow-up testing every few months or annually, while others may only need it once.
Can I fast before this test?
No fasting is required for this blood test. However, if you’re on medications that affect blood clotting, let your healthcare provider know before the test.
  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