What are considered myeloma defining events in the diagnosis of multiple myeloma (MM)?

Updated: May 11, 2021
  • Author: Dhaval Shah, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Answer

Myeloma-defining events include the following  [131] :

  • Hypercalcemia: Serum calcium level > 1 mg/dL (> 0.25 mmol/L) higher than the upper limit of normal or > 2.75 mmol/L (> 11 mg/dL)
  • Abnormal kidney function: Serum creatinine > 2 mg/dL (> 177 μmol/L) or creatinine clearance < 40 mL/min
  • Anemia: Hemoglobin < 10 g/dL, or  > 2 g/dL below the lower limit of normal
  • Bone lesions: One or more osteolytic lesions on skeletal radiography, CT, or PET-CT
  • Biomarkers of malignancy: Clonal bone marrow plasma cells ≥60%  and/or  involved/uninvolved serum FLC ratio ≥100 (involved kappa) or < 0.01 (involved lambda)  and/or one or more focal ≥5 mm lesions on MRI scans

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