Test Details: Proteins are important building blocks of all cells and tissues. Protein electrophoresis is a lab method that separates proteins based on their size and electrical charge. Knowing which proteins are present, absent, elevated, or decreased in body fluids such as blood can help diagnose and/or monitor various diseases and conditions. Immunofixation electrophoresis or immunosubtraction electrophoresis can be used to identify abnormal bands seen on protein electrophoresis, typically in the gamma region, in order to determine whether a type of antibody (immunoglobulin) is abnormally produced.