Bence Jones protein is a monoclonal globulin or immunoglobulin light chain found in the urine, with a molecular weight of 22-24 kDa. Detection of Bence Jones protein may be suggestive of Multiple myeloma or Waldenström's macroglobulinemia. Bence Jones proteins are particularly diagnostic of Multiple myeloma in the context of end-organ manifestations such as renal failure, lytic or punched out bone lesions, anemia, or large numbers of plasma cells in the bone marrow.