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Immunoglobulin G (IgG) Subclass 1 and 3 Quantification by Immunoassay

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

This test measures the levels of specific types of Immunoglobulin G (IgG), a key part of your immune system. IgG helps protect your body from infections and diseases.

Quick summary

["IgG subclasses play a role in immune response; levels may indicate immune function or potential deficiencies."]

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

Key facts at a glance

LOINC
57093-7
Short code
cCP IgA+IgG SerPl IA-aCnc
Synonyms
cCP IgA+IgG SerPl IA-aCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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?

IgG is divided into four subclasses (IgG1, IgG2, IgG3, IgG4), and this test specifically assesses IgG1 and IgG3 concentrations. These subclasses have distinct roles in immune defense, such as antibody-mediated responses and opsonization (marking pathogens for destruction).

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms of immune disorders, such as recurrent infections, autoimmune conditions, or if you’re receiving treatments that could affect your immune system, like chemotherapy or certain medications.

Sample Collection and Preparation

Blood is drawn from a vein, typically in your arm, and sent to a lab for analysis. The test uses an immunoassay method to detect and quantify IgG1 and IgG3 levels in your serum or plasma.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications or supplements that could interfere with results. If you have a bleeding disorder or take blood thinners, let your provider know.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Subclass Levels

Frequently asked questions

IgG1 and IgG3 levels can help diagnose or monitor conditions like hypogammaglobulinemia (low IgG levels), certain autoimmune diseases, or immune deficiencies. Abnormal results may also guide treatment decisions for chronic infections or immune-related disorders.
This test is not typically used alone for diagnosis but may be part of a broader evaluation when symptoms or clinical findings suggest immune system involvement.
How long will results take?
Results are usually available within 1 to 3 business days, depending on lab processing times. Your provider will discuss the findings with you during your follow-up visit.
Can lifestyle changes affect IgG levels?
While diet and overall health can influence immune function, IgG levels are primarily determined by your body’s immune response. Stress, poor nutrition, or chronic illness may indirectly affect immune health but are not directly measured by this test alone.
  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