Diagnostic Workup for Interstitial Increase in Bone Marrow Plasma Cells

Immediate Laboratory Workup Required

The International Myeloma Society recommends determining the exact percentage of plasma cells using both bone marrow aspirate and trephine biopsy, with CD138 immunostaining to accurately quantify plasma cell infiltration, when both procedures are performed, record the highest percentage obtained by either method for diagnostic purposes 3, 4
The American Society of Clinical Oncology suggests establishing clonality through immunoperoxidase staining or immunofluorescence to identify monoclonal immunoglobulin in plasma cell cytoplasm, focusing on light chain restriction (kappa/lambda ratio) 4, 2
The National Comprehensive Cancer Network recommends performing flow cytometry immunophenotyping to assess for abnormal plasma cell markers (CD19-, CD56+, CD38+, CD138+, CD45-), which helps confirm monoclonality 2

The International Myeloma Society recommends serum protein electrophoresis (SPEP) with immunofixation to detect and characterize any M-protein 1, 5, 4
The American Society of Clinical Oncology suggests quantitative immunoglobulin measurement by nephelometry (IgG, IgA, IgM) to assess for suppression of uninvolved immunoglobulins 1, 4
The National Comprehensive Cancer Network recommends serum free light chain assay with kappa/lambda ratio calculation, which is essential for detecting light chain-only disease and risk stratification 4, 2
The International Myeloma Society suggests 24-hour urine collection for total protein, urine protein electrophoresis, and urine immunofixation to detect Bence Jones proteinuria 1, 4

The American Society of Clinical Oncology recommends complete blood count with differential to evaluate for anemia (hemoglobin <10 g/dL or ≥2 g/dL below normal) and assess for rouleaux formation on peripheral smear 1, 5, 6
The National Comprehensive Cancer Network suggests comprehensive metabolic panel including serum calcium (corrected for albumin) to detect hypercalcemia 1, 5
The International Myeloma Society recommends creatinine and calculated creatinine clearance to assess renal function 1, 5

The American Society of Clinical Oncology recommends serum β2-microglobulin for International Staging System classification 3, 4
The National Comprehensive Cancer Network suggests serum lactate dehydrogenase (LDH) which has independent prognostic significance 3, 4

The International Myeloma Society recommends standard metaphase cytogenetics to identify chromosomal abnormalities and distinguish hyperdiploid from non-hyperdiploid disease 3, 4
The American Society of Clinical Oncology suggests fluorescence in situ hybridization (FISH) on CD138-sorted plasma cells with probes for high-risk abnormalities: del(17p13), t(4;14), and t(14;16) 3, 4, 2

The National Comprehensive Cancer Network recommends complete skeletal survey including posteroanterior chest, anteroposterior and lateral views of cervical/thoracic/lumbar spine, humeri, femora, skull (anteroposterior and lateral), and anteroposterior pelvis to detect lytic bone lesions 3, 4, 2
The International Myeloma Society suggests MRI of spine and pelvis should be strongly considered if smoldering myeloma is suspected, as it detects occult lesions that predict more rapid progression to symptomatic disease 3, 7, 4, 2