Multiple myeloma laboratory tests

Laboratory findings consistent with the diagnosis of multiple myeloma include abnormal complete blood count, abnormal basic metabolic panel, elevated monoclonal protein on serum electrophoresis, elevated serum free light chains, and presence of myeloma-specific protein markers by immunohistochemistry or immunophenotyping. Some of the laboratory tests are factors that determine the stage of multiple myeloma.

• Complete blood count with differential
• Serum albumin
• Serum calcium
• Serum electrolytes
• Serum creatinine
• Serum urea
• Serum nitrogen

• 24-hour urine protein
• β₂-microglobulin
• Lactate dehydrogenase
• Serum free light chain assay
• Serum immunofixation electrophoresis
• Serum protein electrophoresis
• Serum quantitative immunoglobulins
• Skeletal survey
• Urine immunofixation electrophoresis
• Urine protein electrophoresis

• Bone marrow aspiration
• Bone marrow biopsy
• Cytogenetics studies
• Flow cytometry
• Fluorescence in situ hybridization
• Immunohistochemistry

• Bone densitometry
• PET/CT or whole-body MRI
• Serum viscosity
• Tissue biopsy of bony or other lesion

• Anemia^[1][2]
• Thrombocytopenia
• Leukopenia

• Rouleaux formation of red blood cells: This is defined as the stacking of 4 or more red blood cells. In healthy individuals, the zeta potential of red blood cells causes intercellular repulsion. However, in patients with multiple myeloma, there are many positively charged paraproteins, which antagonizes the negative charge on red blood cells and allows for stacking.^[1][2]

• Hypercalcemia due to increased osteoclasts activity: This is one of the defining features of end-organ damage in multiple myeloma.
• Increased serum creatinine level due to reduced renal function: This is one of the defining features of end-organ damage in multiple myeloma.
• Abnormal blood urea nitrogen
• High alkaline phosphatase level
• High serum protein level with normal/decreased albumin level: This creates a high protein gap, which is defined as the difference between the albumin level and the total protein level.
• High lactate dehydrogenase: This occurs in stage III multiple myeloma as defined by the Revised-International Staging System (R-ISS).

• Protein electrophoresis is a method that separates proteins in the serum or urine.
• 70% of cases have high levels of IgG
• 20% of cases have high levels of IgA
• 5–10% of cases have only immunoglobulin light chains (Bence Jones proteins)
• Rarely κ- or λ-light chains may be secreted in isolation

• Presence of monoclonal paraprotein on urine protein electrophoresis
• Elevated 24-hour urine protein
• Elevated urine free light chains

• Elevated free kappa light chain
• Elevated free lambda light chain
• Elevated free light chain ratio
• Potentially offers an improvement in monitoring disease progression and response to treatment

• Identifies the type of M-protein or immunoglobulin light chain detected by serum or urine electrophoresis

• Quantitative measurement of IgA, IgG, IgM immunoglobulins to detect immune paresis
• Monoclonal gammopathy (IgA and/or IgG peak)
• Reverse albumin:globulin ratio (low albumin, high globulin)
• Elevated β2-microglobulin level: β2-microglobulin level is one factor that determines the stage of multiple myeloma.

• Multiple myeloma cells are typically CD56, CD38, CD138 positive and CD19 and CD45 negative.