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Total IgG Immunoglobulin (Serum)

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

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

Quick summary

["IgG helps fight infections and is important for long-term immunity."]

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

Key facts at a glance

LOINC
61308-3
Short code
R nigricans IgE/IgE total %
Synonyms
R nigricans IgE/IgE total %
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 IgG Serve in the Body?

IgG antibodies are produced by your immune system in response to infections, vaccines, or other triggers. They play a critical role in defending against bacteria and viruses by neutralizing toxins and marking pathogens for destruction by other immune cells. IgG is also the primary antibody passed from mother to fetus during pregnancy, providing newborns with initial immunity.

Why Might Your Doctor Order This Test?

Your doctor may order this test to assess your immune system function, evaluate immune-related conditions (such as immunodeficiency), monitor treatment responses in autoimmune diseases, or investigate symptoms like frequent infections, fatigue, or unexplained illnesses.

When Might You Need This Test?

You might need this test if you have symptoms like repeated infections, slow wound healing, chronic fatigue, or if you’re undergoing treatment for conditions like lupus, rheumatoid arthritis, or HIV. It may also be part of routine testing for newborns or individuals with suspected immune deficiencies.

What to Expect During the Test

A blood sample is drawn from a vein in your arm, typically by a healthcare professional. The blood is then sent to a lab for analysis. You may feel a slight pinch or discomfort, but it usually takes a few minutes to complete. No special preparation is needed unless instructed otherwise by your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance of IgG Levels

Short name

IgG Total

Frequently asked questions

How are IgG levels interpreted?
IgG levels can be measured in a range of concentrations, but they vary based on age, overall health, and immune status. Low IgG levels may indicate an immune deficiency, while very high levels could suggest chronic infections, autoimmune diseases, or certain medications. Your doctor will review your results in the context of your medical history and symptoms.
What does an abnormal IgG result mean?
An abnormal IgG result may signal an underlying health issue, such as a weakened immune system, chronic infections, or conditions like multiple myeloma. It’s important to discuss your results with your healthcare provider, who can guide further testing or treatment options tailored to your needs.
Can IgG levels change over time?
Yes, IgG levels can fluctuate due to infections, vaccinations, aging, or certain medical conditions. Regular monitoring may be necessary if you have a chronic illness or are undergoing treatment that affects your immune system.
  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