A Low IgG Level

A Low IgG Level: Overview

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.

Low IgG Level