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Total IgG Immunoglobulin (Serum) – Mass Concentration

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

This test measures the amount of Immunoglobulin G (IgG), the most common type of antibody in your blood. IgG helps protect your body from infections and diseases.

Quick summary

["IgG antibodies are vital for long-term immunity and fight infections like bacteria and viruses."]

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

Key facts at a glance

LOINC
56417-9
Short code
Wheat IgG4-mCnc
Synonyms
Wheat IgG4-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 Does IgG Serve in the Body?

IgG antibodies are the primary line of defense in your immune system. They help neutralize toxins, viruses, and bacteria by marking them for destruction by other immune cells. IgG also plays a role in activating the complement system, which enhances the body’s ability to clear pathogens.

Why Might Your Doctor Order This Test?

Your doctor may recommend this test to assess immune function, diagnose or monitor conditions like immunodeficiency, autoimmune diseases, or infections. It can also help evaluate responses to vaccines or treatments for conditions affecting antibody production.

Common Conditions Affecting IgG Levels

Low IgG levels may indicate conditions such as primary immunodeficiency, HIV/AIDS, or chronic infections. High IgG levels can sometimes suggest chronic infections, autoimmune diseases, or certain types of cancer, though this is less common.

What to Expect During the Test

A blood sample will be drawn from a vein in your arm. The process is quick and usually painless. The sample is then sent to a lab for analysis using a technique that measures the mass concentration of IgG in your serum.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance of IgG Levels

Short name

IgG Level

Frequently asked questions

Why is IgG important in diagnosing or managing health conditions?
IgG levels help identify immune system dysfunctions, such as whether your body is producing enough antibodies to fight infections. They can also guide treatment decisions for conditions like chronic infections, autoimmune diseases, or immune deficiencies.
What are the typical reference ranges for IgG?
Reference ranges vary by lab and may not be widely publicized. Your doctor will compare your results to ranges specific to your lab and medical context.
How often should IgG levels be checked?
Your doctor may recommend IgG testing periodically if you have a known immune disorder, are recovering from an infection, or are receiving treatments that affect antibody production.
  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