Immunoglobulin G (IgG) in serum/plasma 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 is the most common antibody in the bloodstream.
["IgG helps fight infections and supports long-term immunity."]
Key facts at a glance
- LOINC
- 82613-1
- Short code
- Honey bee (rApi m) 10 IgE Qn
- Synonyms
- Honey bee (rApi m) 10 IgE Qn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 IgG Measure?
IgG is the primary antibody your immune system produces in response to infections, vaccines, and other immune challenges. It circulates in your blood and provides broad protection against pathogens like bacteria and viruses. Levels can vary based on your immune response, health status, and recent exposure to infections or vaccines.
Why Might You Need This Test?
Doctors may order an IgG test to evaluate immune function, diagnose conditions like immunodeficiency, assess response to vaccines, or monitor chronic diseases that affect antibody production. It can also help identify issues with absorption in the gut (e.g., celiac disease) or immune-related disorders.
How Is the Test Performed?
A blood sample is taken from a vein, usually in your arm. The blood is processed to separate serum or plasma, where IgG levels are measured using a specialized lab technique called nephelometry, which detects light scattering caused by antibodies.
What to Expect Before the Test
There are no special preparations needed for this test. You may have some mild discomfort from the needle, but it typically goes away quickly. If you’re on blood-thinning medication, let your healthcare provider know before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG levels can be low in conditions like severe immunodeficiency, chronic infections, or certain autoimmune diseases. High levels may suggest overactive immune responses, chronic infections, or certain immune disorders. Always discuss results with your doctor, as they’ll consider your full medical history and symptoms.
Short name
IgG Level
Frequently asked questions
What causes IgG levels to be low?
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