The diagnosis of myeloma should be made using the criteria proposed by the International Myeloma Working Group (IMWG). These criteria distinguish between myeloma and MGUS principally on the basis of M protein concentration, percentage of bone marrow plasma cells and the presence or absence of myeloma related organ and tissue impairment (1).
- MGUS
- M-protein in serum <30 g/l
- Bone marrow clonal plasma cells <10 % and low level of plasma cell infiltration in a trephine biopsy (if done)
- No related organ or tissue impairment ((no end organ damage including bone lesions)
- Asymptomatic myeloma
- M-protein in serum >30 g/l and/or Bone marrow clonal plasma cells >10 %
- No related organ or tissue impairment (no end organ damage including bone lesions) or symptoms
- Symptomatic myeloma
- M-protein in serum and/or urine
- Bone marrow (clonal) plasma cells or biopsy proven plasmacytoma
- Myeloma-related organ or tissue impairment (including bone lesions)
Reference:
- Rajkumar SV, Dimopoulos MA, Palumbo A, et al. International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma. Lancet Oncol. 2014 Nov;15(12):e538-48.