Immunoglobulins, Quantitative, IgA, IgG, IgM

This test measures three types of antibodies in your blood—IgA, IgG, and IgM—which are proteins your immune system makes to fight infections. Together, they give your doctor a picture of how well your immune system is working. If levels are too low, it may mean your body has trouble fighting certain infections. If levels are too high, it could point to ongoing inflammation, an autoimmune condition, or, in some cases, a blood cell disorder. Your doctor will look at all three values together, along with your symptoms and other test results, to understand what the findings mean for you.

When elevated: Elevated immunoglobulin levels may indicate polyclonal hypergammaglobulinemia from chronic inflammatory, infectious, or autoimmune conditions, or may suggest a monoclonal gammopathy such as multiple myeloma, Waldenström macroglobulinemia, or MGUS. Disproportionate elevation of a single class warrants further workup with SPEP and immunofixation to exclude a clonal plasma cell disorder. When low: Reduced immunoglobulin levels indicate impaired humoral immunity and are associated with increased susceptibility to encapsulated bacterial infections, recurrent sinopulmonary infections, and poor vaccine responses. Significant hypogammaglobulinemia may necessitate evaluation for primary immunodeficiency or secondary causes and consideration of immunoglobulin replacement therapy.

Immunoglobulin levels can reflect immune readiness during heavy training phases, as intense exercise and overtraining can temporarily suppress IgA and overall immune function, increasing infection risk. Monitoring these antibodies may help identify periods of compromised mucosal immunity that coincide with upper respiratory illness, though single measurements have limited predictive power without serial tracking and clinical context.