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.