How is monoclonal gammopathy of undetermined significance (MGUS) defined?

Monoclonal gammopathy (M spike) with monoclonal (M) protein in serum < 3 g/dL, bone marrow clonal plasma cells < 10%, and absence of related organ or tissue impairment (no end-organ damage, including anemia, hypercalcemia, renal insufficiency, or bone lesions) or amyloidosis related to the plasma cell dyscrasia.