Total Serum Immunoglobulin G (IgG) Level
This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood. IgG helps protect your body from infections and plays a role in long-term immunity.
["IgG helps fight infections and supports immune function by identifying and neutralizing harmful substances."]
Key facts at a glance
- LOINC
- 50329-2
- Short code
- RSV Ag Tiss Ql ImStn
- Synonyms
- RSV Ag Tiss Ql ImStn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- immune-stain
- 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 This Test Measure?
IgG is the most common type of antibody in your blood. It’s produced by your immune system in response to infections and helps provide long-lasting protection against diseases. This test helps doctors assess your immune response, identify immune deficiencies, or monitor conditions like autoimmune diseases or chronic infections.
Why Might You Need This Test?
Your doctor may order this test if you have symptoms like frequent infections, unexplained fatigue, or if you’re being treated for an immune-related condition. It can also be used to monitor immune function in people with conditions like HIV, lupus, or certain cancers.
Sample Collection and Preparation
A blood sample is drawn from a vein, usually in your arm. The blood is then sent to a lab for analysis. No special preparation is needed, but you may be asked to avoid certain medications or foods for a short time before testing, depending on your doctor’s instructions.
What Are the Possible Results?
Results are typically reported as a concentration of IgG in the blood, measured in milligrams per deciliter (mg/dL). While reference ranges vary by lab, lower than expected levels may suggest immune deficiencies, while higher levels could indicate chronic infections, autoimmune diseases, or other conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low IgG levels may indicate a weakened immune system, making you more susceptible to infections. This can happen due to genetic disorders, certain medications, or conditions like HIV/AIDS. High IgG levels can be seen in chronic infections, autoimmune diseases (like rheumatoid arthritis), or as part of normal immune response during recovery from illness. Monitoring IgG levels helps doctors diagnose and manage these conditions effectively.
Short name
IgG Level
Frequently asked questions
How Long Does It Take to Get Results?
What If My Results Are Abnormal?
Does This Test Have Any Risks or Side Effects?
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 16, 2026. · Read our editorial policy