Immunoassay for Immunoglobulin G (IgG) in serum/plasma
This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood. IgG helps fight infections and is important for long-term immunity.
["IgG helps protect your body from infections and long-term illness."]
Key facts at a glance
- LOINC
- 105015-2
- Short code
- CRB-GIM1
- Synonyms
- blaGIM-1 Islt/Spm Ql
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof container; bacterial isolate on appropriate transport media (e.g., Amies or Stuart transport medium); or appropriate swab in transport system (e.g., Copan ESwab)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 87150
- SNOMED
- 443451000124104
- Specimen volume
- 1-2 mL of clinical specimen or visible bacterial growth on solid transport medium; minimum 0.5 mL for liquid specimens
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 24 hours for primary specimens; Bacterial isolates stable at room temperature on appropriate media for up to 48 hours; Frozen (-70°C or below): extended storage for purified nucleic acids
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–72 hours
- Order
- routine
What Does IgG Serve in Your Body?
IgG is the most common type of antibody in your blood. It plays a key role in defending against bacteria and viruses, including those that cause chronic infections. IgG antibodies are also passed from a mother to her baby through breast milk, providing early protection.
Why Might Your Doctor Order This Test?
Your doctor may check your IgG levels if you have symptoms of a weakened immune system, such as frequent infections, slow wound healing, or unexplained fatigue. It can also be used to monitor conditions like certain autoimmune diseases, infections, or to assess immune response after vaccination.
When Might You Receive This Test?
IgG tests are often done as part of a routine blood test or when you have symptoms that suggest an immune system issue. They may also be checked periodically if you have a known condition affecting immunity.
What to Expect Before the Test
No special preparation is needed for this test. You may have a small needle inserted into your arm or hand to draw blood. If you are on blood thinners, let your doctor know before the test.
Reference range
Negative (blaGIM-1 gene not detected)N/A
No special patient preparation required. Sample collection should be performed prior to initiation of antimicrobial therapy when possible. Standard infection control precautions must be observed during specimen collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
IgG Level
Frequently asked questions
How low or high IgG levels can indicate health issues?
What causes IgG levels to change?
Does diet affect 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