Immunoglobulin G (IgG) in Serum

What Does IgG Serology Measure?

IgG is the primary antibody produced by your immune system in response to infections, vaccines, or chronic conditions. It circulates in your bloodstream and provides lasting protection against pathogens. This test helps assess your immune response over time, often used to monitor conditions like autoimmune diseases, chronic infections, or vaccine effectiveness.

Why Might You Need This Test?

Your healthcare provider may order an IgG test to evaluate your immune system function, diagnose conditions like immunodeficiency, track responses to treatments, or investigate unexplained infections. It’s also used in research or specialized testing for conditions affecting antibody levels.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum (the liquid part without clotting factors), which is sent to the lab for testing. This test does not require fasting.

Common Uses and Clinical Contexts

IgG testing is commonly used in diagnosing or managing conditions such as HIV, hepatitis, autoimmune diseases (e.g., lupus), or chronic infections (e.g., tuberculosis). It may also be used to confirm exposure to certain pathogens or assess immune response after vaccination.