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Total Serum Immunoglobulin G (IgG) 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 plays a role in long-term immunity.

Quick summary

["IgG helps fight infections and supports immune function over time."]

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

Key facts at a glance

LOINC
56537-4
Short code
tTG IgG Ser IA-aCnc
Synonyms
tTG IgG Ser IA-aCnc
Category
chemistry
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 Is Immunoglobulin G (IgG)?

IgG is a type of antibody produced by your immune system. It’s the most abundant antibody in your blood and is crucial for defending against bacteria and viruses. Your body produces IgG in response to infections and helps remember past illnesses to prevent future ones.

Why Might You Need This Test?

Doctors may order an IgG test to check for immune system health, diagnose conditions like immunodeficiency, monitor treatment for autoimmune diseases, or evaluate immune responses after vaccination.

When Is an IgG Test Performed?

This test is often done when symptoms like frequent infections, slow wound healing, or unexplained fatigue suggest an immune issue. It may also be part of routine blood work for certain medical conditions or before certain treatments.

How Is the Test Done?

A blood sample is taken from a vein in your arm. The blood is sent to a lab, where it is analyzed to measure the IgG concentration using immunoassay methods.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low IgG levels may indicate a weakened immune system, which can increase susceptibility to infections. High levels could suggest chronic inflammation, certain autoimmune diseases, or overactive immune responses. Regular monitoring helps manage conditions like HIV, lupus, or other immune disorders.

Short name

IgG Level

Frequently asked questions

What could cause abnormal IgG levels?
Abnormal IgG levels can result from immune system disorders (e.g., immunodeficiency), chronic infections, autoimmune diseases, or certain medications. Lifestyle factors like poor nutrition or stress may also influence IgG production.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Your healthcare provider will discuss the results with you during your follow-up visit.
Can diet or supplements affect IgG levels?
Dietary factors like protein intake and vitamin levels (e.g., vitamin D) may indirectly support immune function, but IgG levels are primarily determined by your immune system’s response. Supplements alone won’t change IgG levels unless prescribed by a doctor.
  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