Immunodeficiency is a condition where the immune system cannot effectively fight infections and diseases. It is caused by insufficient production of immunoglobulins (antibodies) such as IgG, IgA, IgM, and IgE, or by defective antibody responses to pathogens and vaccines. The IgG blood test is the most important test for diagnosis because it measures the most abundant antibody in the bloodstream and low levels indicate Common Variable Immunodeficiency or other immune deficiencies.
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Immunodeficiency is caused by insufficient production of antibodies (immunoglobulins) or defective immune cell function that prevents your body from fighting infections effectively. Primary immunodeficiency is genetic and present from birth, caused by inherited mutations in genes responsible for immune system development. Secondary immunodeficiency develops later in life due to factors such as HIV infection, chemotherapy, malnutrition, certain medications like corticosteroids, or chronic diseases like diabetes and kidney disease that weaken immune function over time.
The IgG blood test is the most important test for immunodeficiency because it measures the most abundant antibody in your bloodstream and directly shows whether your immune system can produce adequate protection against infections. Low IgG levels indicate conditions like Common Variable Immunodeficiency, the most common primary immunodeficiency in adults. Additional essential tests include IgA and IgM measurements to assess different antibody classes, and vaccine response tests like Measles Antibody (IgG), Rubella Immune Status, and Varicella-Zoster Virus (VZV) Antibodies to determine if your immune system responds properly to vaccinations. The Candida albicans Ab test measuring IgG, IgA, and IgM is valuable for detecting weakened responses to fungal infections, which commonly affect people with immunodeficiency.
You should get tested if you experience frequent infections that keep coming back, such as four or more ear infections in a year, multiple cases of pneumonia or bronchitis, or sinus infections that require antibiotics repeatedly. Get tested immediately if you have infections that are unusually severe, last longer than expected, or are caused by uncommon organisms that healthy immune systems easily fight off. You should also consider testing if you have a family history of immune disorders, if you notice infections that respond poorly to standard antibiotic treatment, or if you develop chronic diarrhea with unexplained weight loss that suggests your immune system cannot control intestinal pathogens.
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What this means
Your IgG levels are below the optimal range, which may indicate a weakened immune system. This could explain why you're getting sick more often or taking longer to recover from infections. Low IgG means your body has fewer antibodies available to fight off bacteria and viruses effectively.
Recommended actions
Focus on protein-rich foods like lean meats, fish, eggs, and legumes to support antibody production
Ensure adequate vitamins C, D, and zinc through diet or supplements
Get 7-9 hours of quality sleep and manage stress to support immune function
Retest in 3 months and consult an immunologist if levels remain low
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