Substance concentration of immunoglobulin G (IgG) in serum/plasma
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 levels help assess immune function and identify potential deficiencies or excesses."]
Key facts at a glance
- LOINC
- 95673-0
- Short code
- DENV1+2+3+4 IgG Spec Ql IA
- Synonyms
- DENV1+2+3+4 IgG Spec Ql IA
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- 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 IgG Measure?
IgG is the most abundant antibody in your blood, playing a critical role in fighting infections. It’s produced by your immune system to neutralize bacteria and viruses. Measuring IgG helps doctors evaluate your immune response, especially in conditions like HIV, autoimmune diseases, or after vaccination.
Why Might You Need This Test?
Your doctor may order this test if you have symptoms of a weakened immune system (like frequent infections), suspected immunodeficiency, or if you’re being treated for conditions like lupus or other autoimmune disorders. It can also be used to monitor immune response after vaccination or during pregnancy.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The blood is then processed to separate the serum or plasma, where the IgG antibody is measured using a specialized immunoassay technique. The result is compared to standard levels to determine your IgG concentration.
What Are Possible Results?
Results are expressed in grams per deciliter (g/dL) or milligrams per deciliter (mg/dL). While reference ranges vary by lab, lower than expected levels may indicate immunodeficiency, while higher levels could suggest conditions like multiple myeloma or chronic infections.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low IgG levels may indicate a compromised immune system, increasing susceptibility to infections. High IgG levels can be seen in chronic infections, autoimmune diseases, or certain cancers. Monitoring IgG is particularly important for patients with HIV, those undergoing chemotherapy, or those with genetic immune disorders like Common Variable Immunodeficiency (CVID).
Short name
IgG Level
Frequently asked questions
What causes low IgG levels?
What causes high IgG levels?
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