Understanding Lab Tests for Immunodeficiency
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Immunodeficiency is a condition where the immune system's ability to fight infections and diseases is compromised or absent. This can be either primary (present from birth) or secondary (acquired due to other conditions or treatments). Blood tests are fundamental for diagnosing immunodeficiency by measuring various components of the immune system.
Top Recommended Test
IgG
This test measures IgG antibody levels, the most abundant immunoglobulin in blood. Low levels of IgG may indicate a weakened immune system and can lead to recurrent infections. This deficiency could be due to conditions such as Common Variable Immunodeficiency.
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How Blood Tests Diagnose Immunodeficiency
Blood tests can directly measure the levels of antibodies (immunoglobulins) and assess how well the immune system responds to vaccines or infections. These measurements provide critical information about immune function and help identify specific types of immunodeficiency disorders.
Other Relevant Tests
IgD
This test measures IgD immunoglobulin levels in the blood. Low levels of IgD can be associated with certain immunodeficiency conditions, as IgD plays a role in immune response and its deficiency can result in reduced ability to fight off infections.
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IgE
This test measures IgE antibody levels, which are important for immune responses to pathogens. Certain types of immunodeficiency can result in abnormally low levels of IgE, potentially leading to increased susceptibility to infections.
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Rubella Immune Status
This test measures antibodies against rubella virus. If results show low levels of antibodies despite previous vaccination or exposure, it could indicate an immunodeficiency where the immune system is not producing enough antibodies to effectively fight off infections.
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Measles Antibody (IgG)
This test measures IgG antibodies specific to measles virus. If a person doesn't produce adequate measles IgG antibodies in response to infection or vaccination, this could indicate an immunodeficiency where the immune system is not functioning properly.
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Varicella-Zoster Virus (VZV) Antibodies, IgG (Chickenpox)
This test measures IgG antibodies against varicella-zoster virus. A lack of IgG antibodies for VZV in someone who has been exposed to chickenpox or vaccinated may suggest a problem with the immune system's ability to produce antibodies, indicating potential immunodeficiency.
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Rabies Vaccine Response End Point Titer
This test measures the immune response to rabies vaccination. A low titer could indicate a weakened immune system that's not responding effectively to vaccines, which could be due to various immunodeficiency conditions or immunosuppressive treatments.
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Mumps Virus Antibody (IgG)
This test measures IgG antibodies against mumps virus. Weakened antibody response may indicate an immunodeficiency disorder, meaning the body's immune system is not strong enough to mount an appropriate response to infections, including mumps.
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Candida albicans Ab (IgG, IgA, IgM)
This comprehensive test measures IgG, IgA, and IgM antibodies against Candida albicans. Low levels of these antibodies may indicate a weakened immune system, as the body may not be producing adequate antibody responses to fungal infections, which is common in immunodeficiency conditions.
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Understanding Your Test Results
Immunodeficiency testing typically involves measuring baseline immunoglobulin levels and assessing vaccine responses. Low levels of key antibodies or poor vaccine responses can indicate various types of immune system dysfunction that require further evaluation and specialized treatment.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider or immunologist for proper diagnosis, interpretation of test results, and treatment of immunodeficiency disorders.
