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IgG Subclasses

Published: July 27, 2026Updated: August 25, 2026

IgG subclasses measure the levels of the four different subclasses of immunoglobulin G (IgG1, IgG2, IgG3, IgG4) in the blood, which are crucial for immune response and can indicate various immune disorders.

Quick summary

IgG subclasses help diagnose and monitor immune system disorders by measuring the levels of IgG1, IgG2, IgG3, and IgG4.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
mg/dL
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Binding Site IgG Subclasses, Siemens IgG Subclasses
interpretation: {"text":"May indicate a deficiency in one or more IgG subclasses, potentially pointing to an immune disorder such as CVID or specific antibody deficiency.","label":"Low Levels"}; {"text":"Could suggest an overactive immune response or a chronic inflammatory condition, necessitating further investigation.","label":"High Levels"}

IgG subclasses are a group of four distinct types of immunoglobulin G (IgG) antibodies, namely IgG1, IgG2, IgG3, and IgG4. These subclasses play a vital role in the body's immune response by targeting and neutralizing pathogens.

Measuring IgG subclasses can help identify deficiencies or excesses in specific subclasses, which may be indicative of immune system disorders, such as common variable immunodeficiency (CVID) or specific antibody deficiencies.

The reference range for IgG subclasses is typically between 0–2000 mg/dL. Deviations from this range can provide valuable diagnostic information and guide treatment strategies for immune-related conditions.

Frequently asked questions

What is the role of IgG subclasses in the immune system?
IgG subclasses are essential for recognizing and neutralizing pathogens, providing long-term immunity, and playing a critical role in the adaptive immune response.
How are IgG subclass levels tested?
IgG subclass levels are typically measured through a blood test, which can be ordered if an immune deficiency or disorder is suspected.
  1. 1
    Immunoglobulin G SubclassesSource
  2. 2
    IgG Subclass DeficiencySource

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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.

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Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy