Monoclonal gammopathy of undetermined significance (MGUS, unknown or uncertain may be substituted for undetermined), formerly benign monoclonal gammopathy, is a condition in which a paraprotein is found in the blood during standard laboratory tests. It resembles multiple myeloma and similar diseases, but the levels of antibody are lower, the number of plasma cells (white blood cells that secrete antibodies) in the bone marrow is lower, it has no symptoms or problems, and no treatment is indicated. However, multiple myeloma develops at the rate of about 1-2% a year, so doctors recommend monitoring it yearly...