Serum or Plasma Immunoassay for Immunoglobulin G (IgG) Substance Concentration

Why Might This Test Be Ordered?

Your healthcare provider may order this test to check if your immune system is working properly. This could be due to concerns about low IgG levels, which might happen in conditions like chronic infections, certain immune disorders, or after treatments like chemotherapy. It may also be used to monitor immune responses in people with weakened immune systems, such as those with HIV/AIDS or after organ transplants.

What Does a Low or High IgG Level Mean?

Low IgG levels might suggest an immune system that isn’t producing enough antibodies, which can increase the risk of infections. High IgG levels could indicate an overactive immune response, such as in autoimmune diseases or chronic infections. However, these interpretations depend on clinical context and other test results.

How Is This Test Performed?

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate the serum or plasma, which is tested for IgG using an immunoassay method. This method detects the presence and amount of IgG antibodies in your blood.

What Are Common Reasons for Testing?

Common reasons include diagnosing or monitoring conditions affecting the immune system, such as immunodeficiency diseases, autoimmune disorders, or assessing immune responses to treatments like vaccines or medications.