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Immunoblot (Line Blot) for Human Immunoglobulins (IgG, IgA, IgM)

Published: August 9, 2026Updated: August 16, 2026

This test detects specific antibodies (IgG, IgA, IgM) using a line blot assay to identify immune responses, potential infections, or autoimmune conditions.

Quick summary

["Assesses immune system antibodies for diagnostic clarity in infections, allergies, or autoimmune disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
94390-2
Short code
Hu1 IgG CSF Ql Line blot
Synonyms
Hu1 IgG CSF Ql Line blot
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
line-blot
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What This Test Measures

The test identifies three key immunoglobulins—IgG, IgA, and IgM—through a visual line blot. Each immunoglobulin appears as a distinct line if present, helping distinguish between different immune responses or conditions.

Why It’s Ordered

Your healthcare provider may recommend this test if you have symptoms like chronic fatigue, unexplained infections, or suspected autoimmune diseases. It’s also used to monitor immune function in conditions like lupus, rheumatoid arthritis, or chronic infections.

Common Uses and Conditions

Commonly used for diagnosing or confirming autoimmune disorders (e.g., systemic lupus erythematosus), chronic infections (e.g., HIV, hepatitis), or evaluating immune deficiencies. It may also help assess allergic reactions or response to vaccines.

Sample Collection and Preparation

A blood sample is drawn, typically from a vein in your arm. The sample is processed to separate serum or plasma for testing. No special preparation is needed, but fasting may be advised depending on your provider’s instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal levels of IgG, IgA, or IgM can indicate an active immune response (e.g., infection), chronic inflammation, or autoimmune activity. For example, elevated IgM may suggest recent infection, while elevated IgG could indicate long-term exposure or autoimmune disease. IgA levels may be low in certain immune disorders.

Short name

IgG/IgA/IgM Line Blot Profile

Frequently asked questions

What does a positive or abnormal result mean?
A positive or abnormal result means your body may be mounting an unusual immune response. This could signal an infection, autoimmune condition, or immune deficiency. Your provider will interpret results in the context of your symptoms and medical history to guide next steps.
How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Follow-up with your healthcare provider is needed to discuss findings and next steps.
Can I fast before this test?
No fasting is required for this test, but always check with your provider for specific instructions, as some tests may have exceptions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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