Skip to content

Total Immunoglobulin G (IgG) Mass Concentration in Serum

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 helps fight infections and supports immune function; levels may indicate immune response or deficiency."]

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

Key facts at a glance

LOINC
63180-4
Short code
Tobacco IgG-mCnc
Synonyms
Tobacco IgG-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 Is Immunoglobulin G (IgG)?

IgG is the primary antibody produced by your immune system to defend against bacteria, viruses, and toxins. It circulates in your bloodstream and provides long-term immunity. Your body produces IgG in response to infections or vaccines to help your immune system remember past threats.

Why Might You Need This Test?

Doctors may order this test to evaluate your immune system, diagnose conditions like hypogammaglobulinemia (low IgG), or monitor immune responses after treatments like chemotherapy or stem cell transplants. It can also help assess immune function in people with chronic illnesses or those receiving immune-modulating therapies.

When Is This Test Performed?

This test is typically done when you have symptoms of a weakened immune system (e.g., frequent infections, slow wound healing), if you’re undergoing treatments that affect immunity, or as part of a routine checkup for certain conditions. Blood is drawn from a vein in your arm.

What Does a Low or High IgG Level Mean?

Low IgG levels may suggest an immune deficiency or problems with antibody production, increasing your risk of infections. High IgG levels can sometimes indicate chronic infections, autoimmune diseases, or other immune-related conditions. Your doctor will interpret results in the context of your health history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

Could my IgG test results affect my medications?
Yes, IgG levels can influence decisions about certain medications, especially those targeting the immune system (e.g., biologics for autoimmune diseases). Your doctor will discuss how your results may impact your treatment plan.
What if my IgG level is outside the normal range?
If your IgG level is low, you may need further testing or treatments to boost your immune response. If high, additional tests may be needed to identify the underlying cause, such as chronic infections or autoimmune conditions. Follow-up with your healthcare provider is essential.
How often should I get this test?
Frequency depends on your health condition. People with immune deficiencies or chronic illnesses may need this test more often, while others may only need it occasionally. Your doctor will determine the best schedule for you.
  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