Serum or plasma concentration of immunoglobulin G (IgG) by nephelometry
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; levels may indicate immune health or response to treatments."]
Key facts at a glance
- LOINC
- 49082-1
- Short code
- WEEV IgG+IgM Ser-Imp
- Synonyms
- WEEV IgG+IgM Ser-Imp
- 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 most common type of antibody in your blood. It plays a key role in defending against bacteria and viruses. This test helps doctors assess your immune system’s ability to produce antibodies and identify potential immune deficiencies or responses to vaccines or infections.
Why Might You Need This Test?
Your doctor may order this test if you have symptoms of a weakened immune system, such as frequent infections, unexplained fatigue, or if you’re receiving treatments that affect your immune response (e.g., chemotherapy). It can also be used to monitor immune function in conditions like HIV, autoimmune diseases, or after vaccination.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The blood is processed to separate serum or plasma, where the IgG antibody is measured using a specialized lab technique called nephelometry. This method detects the presence and concentration of IgG without needing a specific reaction to identify it.
What Are Common Results?
Results are typically reported as a numerical value representing the IgG concentration in your blood. While reference ranges vary by lab, lower than expected levels may suggest immune deficiencies, and higher levels could be seen in chronic infections or certain immune disorders.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low IgG levels may indicate an immune system that isn’t producing enough antibodies, which can increase your risk of infections. High IgG levels can sometimes be seen in chronic illnesses, such as certain autoimmune diseases, or after repeated infections. Monitoring IgG levels helps doctors diagnose and manage conditions affecting your immune response.
Short name
IgG Level
Frequently asked questions
What Does a Low IgG Level Mean?
What Causes IgG Levels to Be High?
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