diagnostic criteria for MGUS (Monoclonal Gammopathy of Unknown Significance), asymptomatic myeloma and symptomatic myeloma

Last reviewed 12/2021

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:

• 1. Bird JM et al. Guidelines for the diagnosis and management of multiple myeloma 2011. Br J Haematol. 2011;154(1):32-75.