Immunoglobulins (IgA, IgG, IgM)
A comprehensive panel measuring three major antibody types to assess immune system function and detect potential deficiencies or excesses in immune response.
Order this test
LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
This test quantifies the three major classes of immunoglobulins (antibodies) in the blood: IgG, IgA, and IgM. Together, these three classes account for virtually all circulating antibodies and collectively represent the humoral arm of the immune system, the branch responsible for producing proteins that identify and neutralize pathogens.
Each class serves a distinct role. IgG is the most abundant, making up roughly 80% of serum immunoglobulins. It circulates in blood and extracellular fluid, providing long-term protection against bacteria, viruses, and fungi. IgA accounts for about 15% and is concentrated in mucosal secretions (saliva, tears, breast milk, and the lining of the respiratory and digestive tracts), where it acts as a first-line barrier against pathogens entering through mucous membranes. IgM, the smallest fraction at approximately 5%, is the first antibody class produced during an initial immune response and is particularly effective at activating complement and clumping pathogens for rapid clearance. Measuring all three provides a comprehensive view of the body's antibody-producing capacity and can identify immunodeficiency, immune overactivation, or abnormal protein production.
What's included
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals who experience frequent or recurrent infections, particularly respiratory, gastrointestinal, or sinus infections, may benefit from this test to evaluate potential immune system deficiencies.
- Those with a family history of immune deficiency disorders or autoimmune conditions should consider testing to assess their immune status and identify potential hereditary factors.
- Patients with symptoms suggestive of autoimmune disorders, such as chronic fatigue, joint pain, or unexplained inflammation, may need immunoglobulin testing as part of their diagnostic evaluation.
- Healthcare providers may recommend this panel for individuals with chronic conditions like liver disease, kidney disease, or certain cancers that can affect antibody production and immune function.
- People who have been diagnosed with conditions that may affect immune function, such as HIV, diabetes, or those taking immunosuppressive medications, should consider monitoring their immunoglobulin levels regularly.
What to expect
Preparation
No fasting required. Inform healthcare providers about any medications or supplements being taken, especially immunosuppressive drugs, steroids, or recent vaccinations that may affect results.
Sample Type
A standard blood draw from a vein in the arm using a needle. The process typically takes just a few minutes and involves minimal discomfort.
Collection
At the lab location, a trained phlebotomist will collect approximately 2-3 mL of blood in specialized tubes. The sample will be processed to separate serum for analysis.
Turnaround
Results are typically available within 1-3 business days after the lab receives the sample, with no doctor visit required to receive results.
Understanding your results
Results are reported as concentrations for each immunoglobulin class, with reference ranges that vary by age. The clinical significance depends on which classes are elevated or decreased and in what combination. Low levels of one or more classes may indicate primary immunodeficiency, medication-related suppression, or protein-losing conditions. Elevated levels can occur during chronic infections, autoimmune disease, liver disease, or certain blood cancers like multiple myeloma. Healthcare providers evaluate the pattern of results alongside symptoms, infection history, and additional laboratory findings to determine whether the immune system is functioning within expected parameters.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | IgG: 700-1600 mg/dL, IgA: 70-400 mg/dL, IgM: 40-230 mg/dL | The median values of IgA, IgG, and IgM were 2.10 g/L, 9.70 g/L, and 0.85 g/L respectively. Reference ranges may vary by laboratory method and population demographics. |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
The presence of low IgA may be associated with recurrent diarrhea and lung and sinus infections. Low IgG is associated with pyogenic infections, indicating potential immune deficiency. Moderate hypogammaglobulinaemia is often associated with recurrent bacterial infections. Low immunoglobulin levels may suggest primary or secondary immune deficiency, requiring further evaluation and potentially treatment with immunoglobulin replacement therapy.
What does a “High” result mean?
Elevated IgG levels can be seen in chronic active infection or inflammation, or in association with plasma cell disorders. Elevated IgM levels are a nonspecific marker of inflammation, but can be associated with liver disease and certain blood cancers. Elevated immunoglobulin levels may also indicate autoimmune conditions, chronic infections, or certain cancers affecting immune cells. High levels typically suggest an overactive immune response rather than immediate health danger.
Privacy & confidentiality
All immunoglobulin test results are completely confidential and protected under HIPAA regulations. Your results will not be sent to your personal doctor unless you specifically request it, will not be added to your medical records without your consent, and will not appear on insurance statements or explanations of benefits.
Frequently asked questions
Related tests
Complete Blood Count (CBC)
Evaluates overall immune system health including white blood cell counts that work alongside antibodies
View TestC-Reactive Protein (CRP)
Measures inflammation levels that may correlate with elevated immunoglobulin production
View TestAntinuclear Antibodies (ANA)
Screens for autoimmune conditions that may cause abnormal immunoglobulin levels
View TestAutoimmune Panel Basic
Comprehensive autoimmune testing that includes immunoglobulin assessment
View TestRelated conditions
Last reviewed: April 2026
CPT Code: 82784, 82784, 82784
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
Order this test
Choose your preferred lab
LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
Not sure if this is the right test? Contact our care team for guidance.
This page is intentionally kept stable and machine-readable so that researchers, clinicians, and AI systems can rely on it as a reference. See our Citation Policy.