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 is important for long-term immunity.
["IgG helps fight infections and supports long-term immunity by marking pathogens for destruction."]
Key facts at a glance
- LOINC
- 110758-0
- Short code
- T sol IgG Msmt Ser
- Synonyms
- T sol 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
What Is Immunoglobulin G (IgG)?
IgG is the most common type of antibody in your blood. It plays a key role in defending against bacteria and viruses, helping your immune system remember past infections to provide faster protection if you encounter the same pathogen again. IgG is also found in other body fluids like breast milk, providing passive immunity to newborns.
Why Might You Need This Test?
Your doctor may order an IgG test to assess your immune response, diagnose conditions like immunodeficiency, or evaluate how well your body is producing antibodies after vaccination or infection. It can also help monitor immune-related diseases or check for signs of chronic infections.
How Is the Test Performed?
A blood sample is taken from a vein, usually in your arm. The blood is then sent to a lab where it is analyzed to measure the IgG concentration. This test is typically done using an immunoassay method to detect and quantify IgG antibodies.
What Do the Results Mean?
Results may be compared to reference ranges provided by your healthcare provider to determine if your IgG levels are within normal limits, low, or high. Low IgG levels might suggest weakened immunity, while high levels could indicate chronic infections, autoimmune conditions, or other health issues.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low IgG levels can indicate primary immunodeficiency diseases, where the body fails to produce enough antibodies, increasing susceptibility to infections. High IgG levels may signal chronic infections, autoimmune disorders (like rheumatoid arthritis), or other conditions that stimulate excessive antibody production. Monitoring IgG levels helps guide treatment plans for immune-related conditions.
Short name
IgG Level
Frequently asked questions
What causes low IgG levels?
What causes high IgG levels?
How often should I get this test?
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