Serum IgG Immunoglobulin Level (Quantitative)
This test measures the amount of Immunoglobulin G (IgG), the most common type of antibody in your blood. IgG helps fight infections and is important for long-term immunity.
["IgG antibodies protect your body against infections and diseases over time."]
Key facts at a glance
- LOINC
- 109973-8
- Short code
- H capsul IgA Msmt Ser
- Synonyms
- H capsul IgA 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 Does This Test Measure?
IgG is the primary antibody your immune system produces to defend against bacteria, viruses, and toxins. It circulates in your bloodstream and provides long-lasting protection. This test helps doctors assess your immune response, check for infections, or evaluate conditions like immune deficiencies or autoimmune diseases.
Why Might You Need This Test?
Your doctor may order this test if you have symptoms of infection, if you’re recovering from an illness, or if you have a condition that affects your immune system, such as HIV, lupus, or certain cancers. It can also be used to monitor treatment responses or diagnose immune-related disorders.
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 usually takes a few minutes, and you can resume normal activities afterward.
What to Expect During the Test
The blood sample is sent to a lab where it is analyzed to measure IgG levels. The results are typically ready within a few days, depending on lab processing times.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG levels can vary based on infections, immune responses, age, and underlying health conditions. Low IgG levels may indicate an immune deficiency, while very high levels could suggest chronic infections or certain immune disorders. Always discuss your results with your healthcare provider for personalized interpretation.
Short name
IgG Level
Frequently asked questions
When could my IgG levels be checked?
What do my IgG results mean?
Can IgG levels change over time?
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