Immunoglobulins (Ig) are also known as antibodies. These proteins protect the body against disease. Certain diseases result in the growth of an excess number of antibody-producing cells. In some diseases, these cells can produce a large number of antibodies that are all exactly the same. Protein electrophoresis is used to identify the presence of abnormal proteins, to identify the absence of normal proteins, and to determine when different groups of proteins are present in unusually high or low amounts in blood or other body fluids. Protein electrophoresis separates proteins based on their size and electrical charge, and is often used to diagnose multiple myeloma or Waldenstrom’s macroglobulinemia, when symptoms of the disorders are present.