Immunoglobulin G (IgG) Subclass 1, Serum Concentration

What Is IgG1 Used For?

IgG1 is primarily measured to assess immune function, particularly the effectiveness of your antibody response. It can help diagnose or monitor conditions like autoimmune diseases, infections, or certain immune deficiencies. Doctors may also check IgG1 levels if you have symptoms of a weakened immune system or if you’re receiving treatments that affect antibodies.

When Might You Need This Test?

Your healthcare provider might order an IgG1 test if you have symptoms such as frequent infections, unexplained fatigue, or if you’re being treated for conditions like lupus, rheumatoid arthritis, or HIV. It may also be part of a broader immune evaluation, especially in children or adults with suspected immune disorders.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. The blood is then sent to a lab where it is analyzed to measure the concentration of IgG1 antibodies. The process is quick and typically done in a doctor’s office or clinic.

What Do Results Mean?

Results show the amount of IgG1 in your blood. While specific reference ranges can vary by lab, lower than expected levels may suggest an immune deficiency, while higher levels could indicate chronic infections, certain autoimmune diseases, or other conditions affecting antibody production.