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Serum or plasma concentration of immunoglobulin G (IgG) antibodies

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

This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood. IgG helps fight infections and is important for long-term immunity.

Quick summary

["IgG antibodies protect your body from infections and help maintain immunity over time."]

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

Key facts at a glance

LOINC
10402-6
Short code
ISG Gvn Vol
Synonyms
ISG Gvn Vol
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

What Does This Test Measure?

IgG antibodies are a key part of your immune system. They are produced by your immune cells to help your body recognize and fight off bacteria, viruses, and other foreign substances. This test helps assess your overall immune response and identify if your body is producing enough IgG to protect you.

Why Might You Need This Test?

Doctors may order this test to evaluate immune function, diagnose conditions like immunodeficiency, check for infections, or monitor treatment responses in people with weakened immune systems.

Common Reasons for Testing

Common reasons include evaluating immune deficiencies, diagnosing autoimmune diseases, assessing immune responses after vaccination, or monitoring chronic conditions that affect antibody production.

Sample Collection and Preparation

A blood sample is typically collected from a vein in your arm. The blood is processed to separate serum (liquid part after clotting) or plasma (liquid part before clotting) for testing. This test can be done on either serum or plasma.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low IgG levels may indicate an immune deficiency, chronic infections, or conditions like celiac disease or malabsorption. High IgG levels can sometimes suggest chronic inflammation, autoimmune disorders, or exposure to repeated infections. Monitoring IgG levels helps guide treatment decisions for immune-related conditions.

Short name

IgG Antibody Level

Frequently asked questions

What Are Normal IgG Levels?
Normal IgG levels vary among individuals and can be influenced by age, overall health, and other medical conditions. Your doctor will interpret the results in relation to your specific health needs.
Can Diet Affect IgG Levels?
Diet can indirectly affect immune function, but it does not directly alter IgG levels. A balanced diet supports overall immune health, which may influence antibody production indirectly.
How Often Should I Get This Test?
Your doctor will determine the frequency of testing based on your medical history, symptoms, and treatment plan. Regular monitoring may be needed if you have a chronic condition affecting immunity.
  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