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Total Immunoglobulin G (IgG) Subclass Measurement (Serum/Plasma)

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

This test measures different types of Immunoglobulin G (IgG), a key protein in your immune system, often broken down into subclasses for detailed assessment.

Quick summary

["IgG subclasses help identify specific immune function strengths or weaknesses."]

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

Key facts at a glance

LOINC
107562-1
Short code
TIF1-gamma Ab SerPl Ql
Synonyms
TIF1-gamma Ab SerPl Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Might Be Ordered

Your doctor may recommend this test if you have symptoms like frequent infections, autoimmune conditions, or if you’re being evaluated for immune-related disorders. It can also be part of monitoring for certain diseases or treatments that affect antibody production.

What to Expect Before the Test

No special preparation is needed, but you may fast for 8–12 hours before the blood draw if instructed. Bring your lab requisition to the appointment for clarity on your specific test order.

What the Test Measures

IgG is divided into four main subclasses (IgG1, IgG2, IgG3, IgG4), each with distinct roles. This test evaluates the concentration of these subclasses in your blood, often using immunoassay methods to detect and quantify them.

Common Conditions Monitored

Low IgG subclass levels may suggest immune deficiencies, while elevated levels could indicate chronic infections, certain cancers, or overactive immune responses. Some subclasses are particularly important for fighting specific types of bacteria or viruses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Subclass Levels

Frequently asked questions

What does a low or high IgG subclass result mean?
A low IgG subclass may indicate an immune deficiency, which could make you more prone to infections. A high IgG subclass might suggest chronic inflammation, infection, or an overactive immune response. Your doctor will interpret results in the context of your overall health and symptoms.
How often should I get this test?
The frequency depends on your medical condition. Some patients need this test yearly, while others may require it more often if they’re on long-term treatments or have ongoing health concerns. Follow your doctor’s recommendations.
Can lifestyle changes affect IgG subclass levels?
While diet and exercise can support overall immune health, IgG subclass levels are primarily influenced by genetic factors, infections, and immune system activity. Your doctor may suggest general immune-boosting strategies, but they won’t directly change test results.
  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