IgG stands for immunoglobulin G, one of the classes of immunoglobulins (also called antibodies) that are in the blood. IgG is the major antibody found in the blood that can enter tissues. It coats germs, helping other cells to seek and destroy them.
Causes and Development
Low levels of IgG occur in macroglobulinemia. In this disease, the high levels of IgM antibodies
suppress the growth of cells that produce IgG. Other conditions that can result in low levels of IgG include some types of leukemia
and a type of kidney
damage (nephrotic syndrome). Rarely, some people are born with a deficiency of IgG antibodies. These people are more susceptible to infections.
Diagnosis and Tests
The 'low', 'normal' and 'high' ranges vary with age, and are also lab-specific. However, a reasonable normal range is 620-1400mg/dl.