Immunoglobulin G (IgG) Protein Mass Concentration
This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood. IgG is important for fighting infections and long-term immunity.
["IgG helps protect your body from diseases and infections over time."]
Key facts at a glance
- LOINC
- 54901-4
- Short code
- IgG Prt-mCnc
- Synonyms
- IgG Prt-mCnc
- 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 IgG Serve in Your Body?
IgG antibodies are the most abundant type of antibody in your blood. They play a key role in providing long-term immunity by helping your immune system remember past infections, which can prevent future illnesses. IgG is also involved in protecting against toxins and foreign substances, such as bacteria and viruses.
When Might You Need This Test?
Doctors may order an IgG test to check for low or high levels, which can happen in conditions like immune deficiencies, chronic infections, or certain autoimmune diseases. It may also be used to monitor treatment responses in patients with weakened immune systems.
Common Reasons for Testing
Common reasons include diagnosing or managing conditions such as HIV, certain cancers (like lymphoma), chronic infections, or immune system disorders. It can also be part of routine monitoring for patients on immunosuppressive therapy.
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. If you are on blood thinners or have a history of bleeding issues, let your healthcare provider know.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low IgG levels may indicate a weakened immune system, potentially due to conditions like primary immunodeficiency, HIV/AIDS, or certain cancers. High IgG levels can sometimes be seen in chronic infections, autoimmune diseases, or as a response to repeated vaccinations. Monitoring IgG levels helps healthcare providers tailor treatments to support immune function and manage health conditions effectively.
Short name
IgG Level
Frequently asked questions
Why might my IgG test results be abnormal?
How often should I get this test?
Can lifestyle changes affect my IgG levels?
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