Line Blot Immunoassay for Immunoglobulin G (IgG) Subclasses (Serum)
This test measures the levels of specific subclasses of Immunoglobulin G (IgG), a key antibody protein in your immune system, using a line blot immunoassay method. It helps assess immune function and identify potential deficiencies or abnormalities.
["This test evaluates specific IgG subclasses to support diagnosis of immune disorders."]
Key facts at a glance
- LOINC
- 82407-8
- Short code
- GM4 IgG Ser Ql Line blot
- Synonyms
- GM4 IgG Ser Ql Line blot
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- line-blot
- 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
Why This Test Is Done
Your healthcare provider may recommend this test if you have symptoms or conditions linked to immune system issues, such as recurrent infections, autoimmune diseases, or suspected IgG subclass deficiencies. It may also be used to monitor treatment responses in certain immune-related conditions.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, typically drawn from a vein in your arm. The sample is processed into serum for testing. If you’re on blood-thinning medication, inform your provider beforehand.
What the Test Results Mean
Results show the presence or relative concentration of IgG subclasses (IgG1, IgG2, IgG3, IgG4) via a visual line blot. Abnormal levels may indicate immune dysfunction, antibody class switching disorders, or other immune-related conditions.
Common Conditions Linked to This Test
This test is often used to diagnose or monitor conditions like common variable immunodeficiency (CVID), hypogammaglobulinemia, or autoimmune diseases where IgG subclass patterns are abnormal. It may also help evaluate immune responses to vaccines.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG subclass testing is critical for identifying specific immune deficiencies or imbalances that standard IgG levels might miss. For example, low IgG2 levels are often associated with recurrent sinus or respiratory infections, while elevated IgG4 may suggest autoimmune conditions like IgG4-related disease. Early detection allows for targeted therapies to improve immune function and reduce complications.
Short name
IgG Subclass Line Blot
Frequently asked questions
What does a line blot immunoassay detect in this test?
How long does it take to get results from this test?
Can this test be done on urine or saliva instead of blood?
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