Total IgG Immunoglobulin Subclass Measurement (Serum/Plasma)
This test measures different types of Immunoglobulin G (IgG), a key antibody protein in your blood that helps fight infections and diseases.
["IgG subclasses help identify immune system function and potential deficiencies."]
Key facts at a glance
- LOINC
- 35537-0
- Short code
- Wheat IgG-mCnc
- Synonyms
- Wheat 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 IgG Subclasses Are Measured?
IgG is divided into four subclasses (IgG1, IgG2, IgG3, IgG4), each with distinct roles in immunity. This test evaluates their relative concentrations in your blood, often used to assess immune response, allergies, or chronic conditions.
Why Might You Need This Test?
Doctors may order this test if you have symptoms like frequent infections, poor wound healing, or autoimmune disorders. It can also help diagnose or monitor conditions like common variable immunodeficiency (CVID) or certain allergies.
Sample Collection and Preparation
A blood sample is drawn from your arm, placed in a tube, and sent to a lab. The blood is separated into serum or plasma for testing, often analyzed using immunoassay methods to detect IgG subclass levels.
What to Expect Before the Test
No special preparation is needed, but inform your doctor about any medications (especially steroids) or recent illnesses that could affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
IgG Subclass Levels
Frequently asked questions
IgG subclass levels can reveal immune system imbalances. For example, low IgG2 may indicate trouble fighting bacterial infections, while high IgG4 could suggest allergies or autoimmune reactions. These findings guide treatment plans for immune-related conditions.
A general IgG test measures total IgG, while this test breaks down IgG into its four subclasses (IgG1–IgG4). This detailed breakdown helps pinpoint specific immune system issues that a total IgG test might miss.
Yes, IgG subclass levels can fluctuate due to infections, medications (like steroids), or chronic illnesses. Regular monitoring may be needed if you have a condition affecting immunity.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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