Total Immunoglobulin G (IgG) in Serum

What Does This Test Measure?

IgG is the most common type of antibody in your blood. It plays a key role in defending against bacteria and viruses. This test helps doctors assess your immune system’s ability to produce antibodies, which can be important for diagnosing or monitoring conditions like immune deficiencies, infections, or certain autoimmune diseases.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms of a weakened immune system, such as frequent infections, unusual fatigue, or if you’re being treated for an immune-related condition. It can also be used to monitor immune responses before or after treatments like chemotherapy or organ transplants.

What to Expect Before the Test

No special preparation is usually needed for this blood test. You may be asked to fast before the test if it’s part of a larger panel, but your provider will let you know if that applies. Bring any medications you’re taking to your appointment.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. The blood will be sent to a lab, where it will be analyzed to measure the IgG levels. The process typically takes a few minutes, and you may feel a slight pinch or discomfort during the draw.