Abstract
Many previous studies of normative values in adults have suggested that race, age, sex, and environment all have significant effects on the mean values for IgG, IgA, IgM, and IgE in various groups of individuals. Single radial immunodiffusion is the technique most widely used to quantitate immunoglobulins of the three major classes (IgG, IgM, and IgA) in sera. Measurements have been expressed in terms of mass concentration, as percentages of the mean normal adult value, and in arbitrary international units. To improve agreement among laboratories, the WHO has supported the distribution of an International Reference Preparation for the Human Immunoglobulins IgG, IgA, and IgM, and similar (separate) preparations for IgD and IgE.