Total Immunoglobulin G (IgG) in Serum
This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood. IgG helps protect your body from infections by fighting bacteria and viruses.
["IgG levels help assess immune function and identify deficiencies or excesses that may affect your health."]
Key facts at a glance
- LOINC
- 41203-1
- Short code
- Yellow Jacket IgE/IgE total %
- Synonyms
- Yellow Jacket IgE/IgE total %
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 22
- Ref high
- 198
- Critical range
- — – 10000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82553
- 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 most common type of antibody in your blood. It plays a key role in long-term immunity by helping your body remember past infections and respond more effectively if you encounter the same germs again. Antibodies like IgG are produced by your immune system to recognize and neutralize harmful substances, such as bacteria and viruses.
Why Might You Need This Test?
Your doctor may order an IgG test if you have symptoms of a weakened immune system, such as frequent infections, slow wound healing, or unexplained fatigue. It can also be used to diagnose or monitor conditions like HIV, certain autoimmune diseases, or immune deficiencies.
When Is This Test Performed?
A blood sample is taken from a vein in your arm, usually in a doctor’s office or clinic. The blood is then sent to a lab for analysis. Results are typically available within a few days.
What Does a Low or High IgG Level Mean?
Low IgG levels may indicate an immune system disorder, such as a primary immunodeficiency or chronic illness that affects antibody production. High IgG levels can sometimes suggest chronic infections, certain autoimmune diseases, or overactive immune responses.
Reference range
Adult males: 22-198 U/L; Females: 22-198 U/LN/A
No special preparation required. Inform provider of any chest pain or symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG levels are crucial for diagnosing and managing conditions that impact immunity. Low IgG can lead to recurrent infections, while high IgG may indicate chronic inflammation or immune-related disorders. Monitoring IgG helps guide treatment plans for conditions like HIV, autoimmune diseases, or congenital immune deficiencies.
Short name
IgG Level
Frequently asked questions
How is this test performed?
What are the typical reference ranges?
Can lifestyle changes affect IgG levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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 17, 2026. · Read our editorial policy