The bone marrow smear shown here demonstrates increased numbers of plasma cells in a case of multiple myeloma, most of which appear similar to normal plasma cells, though there is an abnormal double nucleated plasma cell at the far right. These plasma cells are differentiated enough to produce immunoglobulin. Since myeloma is a monoclonal proliferation of plasma cells, the immunoglobulin produced will be of one kind, such as IgG kappa. The increased immunoglobulin appears as a monoclonal 'spike' on serum and/or urine protein electrophoresis that can be further characterized as to type by immunoelectrophoresis. The excessive amount of light chains produced are excreted and detected in the urine as Bence-Jones proteinuria. The standard urine 'dipstick' easily detects albumin, but can miss globular proteins.