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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), a type of antibody in your blood. IgG helps fight infections and is important for long-term immunity.

Quick summary

["IgG levels help assess your immune system’s strength and detect potential deficiencies or overproduction."]

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

Key facts at a glance

LOINC
110125-2
Short code
T canis IgG Msmt Ser
Synonyms
T canis IgG Msmt Ser
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

Why This Test Is Done

Your doctor may order this test to check for immune system problems, such as low IgG levels (hypogammaglobulinemia), which can make you more prone to infections. It may also be used to monitor conditions like chronic infections, autoimmune diseases, or after treatments like chemotherapy that weaken the immune system.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm, and a small amount of blood will be drawn. This usually takes a few minutes and is done in a clinic or lab.

What the Results Mean

Results are compared to standard ranges for healthy adults. Very low IgG levels may indicate an immune disorder, while very high levels could suggest chronic infections, certain cancers, or other conditions. Your doctor will discuss the results with you.

Common Conditions Linked to IgG Levels

Low IgG levels can be linked to conditions like common variable immunodeficiency (CVID), HIV/AIDS, or other immune deficiencies. High IgG levels may be seen in chronic infections, inflammatory diseases, or certain cancers.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

What causes IgG levels to be too low?
IgG levels may drop due to genetic immune disorders, treatments that weaken the immune system (like chemotherapy), chronic illnesses (like HIV), or conditions that affect the liver or kidneys.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition, treatment plan, or symptoms. Regular monitoring may be recommended if you have an immune disorder or are at higher risk for infections.
Can diet affect IgG levels?
Diet can influence overall immune health, but it does not directly affect IgG levels. Eating a balanced diet rich in vitamins, minerals, and proteins supports a healthy immune system, though IgG is primarily produced by the body’s immune response.
  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