A paraprotein is an abnormal protein in the urine or blood, most often associated with multiple myeloma. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Urine is liquid waste excreted by the kidneys and eventually expelled from the body in a process known as urination. ... Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... Multiple myeloma (also known simply as myeloma or plasma cell myeloma) is a presently incurable hematological malignancy of plasma cells, the cells of the immune system that produce antibodies. ...

These are immunoglobulins or immunoglobulin light-chains that are produced by the clonal proliferation of plasma cells. Paraproteins form a narrow band, or 'spike' in protein electrophoresis as they are all the exact same protein. Schematic of antibody binding to an antigen An antibody is a protein complex used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... Plasma cells are B lymphocytes that secrete immunoglobulins (antibodies). ... Please see gel electrophoresis for the principles of electrophoresis Schematic representation of a protein electrophoresis gel In chemistry and medicine, protein electrophoresis is a method of analysing a mixture of proteins by means of gel electrophoresis, mainly in blood serum (blood plasma is not suitable). ...

Light-chains in the urine are called Bence Jones proteins.