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 diseases.
["IgG helps fight infections and supports immune function."]
Key facts at a glance
- LOINC
- 110128-6
- Short code
- S pneum Da 4 IgG Msmt Ser
- Synonyms
- S pneum Da 4 IgG Msmt Ser
- Category
- coagulation
- 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 Does This Test Measure?
IgG is the most common type of antibody in your blood. It plays a key role in defending your body against bacteria and viruses. This test helps doctors assess your immune system’s ability to produce antibodies, which is important for fighting infections and maintaining overall health.
Why Might Your Doctor Order This Test?
Your doctor may order an IgG test to check for immune system issues, such as low antibody levels that could make you more susceptible to infections. It may also be used in diagnosing or monitoring conditions like HIV, autoimmune diseases, or certain types of cancer.
Common Reasons for Testing
Common reasons include evaluating immune function, diagnosing infections or immune disorders, monitoring treatment progress in conditions like HIV or cancer, or checking for deficiencies that could affect your health.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. The process is quick and usually painless.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG levels can provide important clues about your immune health. Low IgG levels may indicate a weakened immune response, while high levels could be seen in certain infections, chronic diseases, or immune system overactivity. This test is often used alongside other tests to diagnose or guide treatment plans.
Short name
IgG Level
Frequently asked questions
What does an abnormal IgG level mean?
How often should I get this test?
Can diet or lifestyle 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 16, 2026. · Read our editorial policy