What are the IMWG diagnostic criteria for multiple myeloma?

Updated: Sep 12, 2018
  • Author: Mohammad I Abu Zaid, MBBS; Chief Editor: Emmanuel C Besa, MD  more...
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The IMWG has established definitions of multiple myeloma and smoldering multiple myeloma. Multiple myeloma is defined as clonal bone marrow plasma cells ≥10% or biopsy-proven bony or extramedullary plasmacytoma, and one or more myeloma-defining events and biomarkers of malignancy.

A myeloma-defining event consists of evidence of end-organ damage that can be attributed to the underlying plasma cell proliferative disorder, specifically any of the following:

  • Hypercalcemia: serum calcium > 0.25 mmol/L (> 1 mg/dL) higher than the upper limit of normal or > 2.75 mmol/L (> 11 mg/dL)
  • Renal insufficiency: creatinine clearance <  40 mL per min or serum creatinine > 177 μmol/L (> 2 mg/dL)
  • Anemia: hemoglobin value of > 20 g/L below the lower limit of normal, or a hemoglobin value <  100 g/L
  • Bone lesions: one or more osteolytic lesions on skeletal radiography, CT, or PET-CT

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