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 is important for fighting infections and providing long-term immunity.
["IgG helps protect your body from diseases and infections by identifying and neutralizing harmful substances."]
Key facts at a glance
- LOINC
- 46277-0
- Short code
- Rh Imm Gl gvn by Provider
- Synonyms
- Rh Imm Gl gvn by Provider
- 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 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, which can be important for diagnosing or monitoring conditions like infections, autoimmune diseases, or immune deficiencies.
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, unusual fatigue, or if you’re being treated for conditions like lupus, HIV, or other immune-related disorders. It can also be used to check for certain infections or to monitor immune responses after vaccination.
What to Expect Before the Test
No special preparation is usually needed for this test. You may have a small needle inserted into your arm or vein to draw blood. If you’re taking blood from your arm, you might feel a slight pinch or sting. If you’re having blood drawn from your vein, you may feel a brief pinch or pressure.
What Happens During the Test?
The blood sample is sent to a lab where it is analyzed using a specialized technique called nephelometry. This method measures the amount of IgG in your blood by detecting how it scatters light, helping to determine your antibody levels accurately.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG levels can provide important information about your immune health. Low levels may suggest an immune deficiency or an ongoing infection, while high levels could indicate chronic infections, autoimmune diseases, or certain immune responses like those seen after vaccination.
Short name
IgG Level
Frequently asked questions
Will I experience any side effects from this test?
How long will it take to get my results?
Can I eat or drink before 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