Immunoglobulin G （IgG） is a type of antibody. IgG is the most common type of antibody found in blood circulation. IgG molecules are created and released by plasma B cells. There are 4 subclasses: IgG1 （66%）, IgG2 （23%）, IgG3 （7%） and IgG4 （4%）. This is the most abundant immunoglobulin and is approximately equally distributed in blood and in tissue liquids, constituting 75% of serum immunoglobulins in humans. This kit is for the quantitative measurement of human total IgG in Human serum, plasma and supernatant from cell cultures.