Monoclonal gammopathy of undetermined significance (MGUS):
(1) A monoclonal protein is present.
(2) monoclonal protein levels: IgG <= 3.5 g/dL; IgA <= 2 g/dL; Bence-Jones protein < 1 gram per 24 hours
(3) bone marrow plasma cells < 10% and no plasma cell aggregates
(4) no bone lesions
(5) no symptoms and no associated disease features
(6) labelling index < 1%
Multiple myeloma:
(1) A monoclonal protein is present.
(2) The patient is symptomatic .
(3) Diagnostic criteria are present (see below):
(3a) >= 1 major criteria AND >= 1 minor criteria, OR
(3b) >= 3 minor criteria (must include bone marrow plasmacytosis and monoclonal protein)
Multiple myeloma major criteria:
(1) plasmacytoma on tissue biopsy
(2) bone marrow plasmacytosis > 30% plasma cells
(3) monoclonal protein present: serum IgG > 3.5 g/dL, serum IgA > 2 g/dL, urine kappa or lambda light chain >= 1 g per 24 hours in the absence of amyloidosis
Multiple myeloma minor criteria:
(1) bone marrow plasmacytosis of 10-30%
(2) monoclonal protein present: serum IgG <= 3.5 g/dL, serum IgA <= 2 g/dL, urine kappa or lambda light chain < 1 g per 24 hours in the absence of amyloidosis
(3) lytic bone lesions present
(4) depressed non-monoclonal immunoglobulins: IgG < 600 mg/dL, IgA < 100 mg/dL, IgM < 50 mg/dL
Indolent myeloma:
(1) no bone lesions, or only limited bone lesions ( <= 3 lytic lesions)
(2) no compression fractures
(3) monoclonal protein levels: IgG < 7 mg/dL; IgA < 5 mg/dL
(4) no symptoms or associated disease features
(5) labelling index < 1%
Smoldering myeloma:
(1) no bone lesions
(2) bone marrow plasma cells from 10-30%
(3) monoclonal proteins levels: IgG < 7 mg/dL; IgA < 5 mg/dL
(4) no symptoms or associated disease features
The absence of symptoms or associated disease features (used in the definition of MGUS, indolent or smoldering myeloma) require all of the following:
(1) Karnofsky performance status > 70%
(2) hemoglobin > 10 g/dL
(3) serum calcium normal
(4) serum creatinine < 2 mg/dL
(5) no opportunistic infections
