
The gamma-globulin band as seen in conventional serum protein electrophoresis consists of 5 immunoglobulins. In normal serum, about 5% is immunoglobulin M (IgM)Elevations of IgM may be due to polyclonal immunoglobulin production. Monoclonal elevations of IgM occur in macroglobulinemia.Monoclonal gammopathies of all types may lead to a spike in the gamma-globulin zone seen on serum protein electrophoresis.Decreased immunoglobulin levels are found in patients with congenital deficiencies.