Total IgG

The Total Immunoglobulin G (IgG) serum test measures the overall level of IgG antibodies in your blood. IgG is the most abundant antibody in the bloodstream and plays a crucial role in fighting off infections. It provides long-term immunity by recognizing and neutralizing pathogens such as viruses and bacteria. Abnormal IgG levels can indicate various health conditions, including immune deficiencies, chronic infections, or autoimmune disorders.

This test is commonly ordered to evaluate the immune status of a patient or to diagnose and monitor immune system disorders. It helps detect whether the immune system is overactive, underactive, or functioning normally. It is often used alongside other immunoglobulin tests (IgA, IgM) to provide a comprehensive view of the immune response and to investigate recurrent infections, chronic illnesses, or autoimmune diseases.

An elevated IgG level may indicate a chronic infection, autoimmune condition, liver disease, or multiple myeloma. It suggests an ongoing immune response. For example, diseases such as rheumatoid arthritis, lupus, or hepatitis may cause increased IgG levels. Interpretation of results must be done in conjunction with clinical history and other laboratory findings to identify the underlying cause.

Low IgG levels can suggest a primary immunodeficiency such as Common Variable Immunodeficiency (CVID) or a secondary cause like chemotherapy or certain medications. It may result in a person being more susceptible to infections. Patients with low IgG often experience recurrent bacterial infections, especially of the lungs and sinuses, and may require immunoglobulin replacement therapy.

The Total IgG serum test is performed on a blood sample taken from a vein, usually in the arm. No special preparation is required before the test. It is a simple, routine blood test, and results are usually available within a few days. The test is safe, with minimal risk aside from standard risks associated with blood draws such as bruising or slight discomfort.