From the Guidelines
Multiple myeloma is diagnosed based on the presence of clonal bone marrow plasma cells ≥10% or biopsy-proven plasmacytoma, plus one or more myeloma-defining events (hypercalcemia, renal insufficiency, anemia, or bone lesions) or biomarkers of malignancy (≥60% clonal plasma cells, involved/uninvolved serum free light chain ratio ≥100, or >1 focal lesion on MRI) as per the International Myeloma Working Group (IMWG) diagnostic criteria 1. The diagnostic process for multiple myeloma typically involves a combination of:
- Blood tests, including complete blood count (CBC), comprehensive metabolic panel, serum protein electrophoresis (SPEP), immunofixation electrophoresis, and serum free light chain assay to detect abnormal proteins (M proteins) produced by myeloma cells
- Urine tests, such as urine protein electrophoresis (UPEP) and 24-hour urine collection, to identify Bence Jones proteins
- Bone marrow biopsy to examine the percentage of plasma cells in the bone marrow
- Imaging studies, including X-rays, MRI, CT scans, or PET scans, to detect bone lesions or damage The IMWG diagnostic criteria, as updated in 2020, provide a comprehensive framework for diagnosing multiple myeloma 1. Key diagnostic criteria include:
- Clonal bone marrow plasma cells ≥10% or biopsy-proven plasmacytoma
- Myeloma-defining events, such as hypercalcemia, renal insufficiency, anemia, or bone lesions
- Biomarkers of malignancy, including ≥60% clonal plasma cells, involved/uninvolved serum free light chain ratio ≥100, or >1 focal lesion on MRI Early diagnosis is crucial, as it allows for prompt treatment initiation, potentially improving outcomes and quality of life for patients with this progressive blood cancer 1.
From the Research
Diagnostic Criteria for Multiple Myeloma
The diagnostic criteria for multiple myeloma include:
- Presence of ≥10% clonal bone marrow plasma cells or a biopsy-proven plasmacytoma plus evidence of one or more multiple myeloma defining events (MDE) 2
- MDEs include:
- CRAB (hypercalcemia, renal failure, anemia, or lytic bone lesions) attributable to the plasma cell disorder
- Bone marrow clonal plasmacytosis ≥60%
- Serum involved/uninvolved free light chain (FLC) ratio ≥100 (provided involved FLC is ≥100 mg/L and urine monoclonal protein is ≥200 mg/24 h)
1 focal lesion on magnetic resonance imaging 2
- Evaluation of patients with possible multiple myeloma includes:
- Measurement of hemoglobin, serum creatinine, serum calcium, and serum free light chain levels
- Serum protein electrophoresis with immunofixation
- 24-hour urine protein electrophoresis
- Full-body skeletal imaging with computed tomography, positron emission tomography, or magnetic resonance imaging 3
Laboratory Tests and Imaging
Laboratory tests and imaging studies used in the diagnosis of multiple myeloma include:
- Serum or urine protein electrophoresis or immunofixation 4, 5
- Bone marrow aspirate analysis 4, 5
- Skeletal radiographs to reveal lytic lesions, vertebral compression fractures, and osteoporosis 4
- Magnetic resonance imaging and positron emission tomography or computed tomography to evaluate patients with myeloma 4, 3
- Complete blood count with differential, serum chemistries, creatinine, lactate dehydrogenase, and beta2-microglobulin tests 5
Staging and Risk Stratification
The Revised International Staging System combines data from serum biomarkers β2 microglobulin, albumin, and lactate dehydrogenase in conjunction with malignant plasma cell genomic features to assess estimated progression-free survival and overall survival 3