Multiple myeloma laboratory tests: Difference between revisions
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===Quantitative immunoglobulins=== | ===Quantitative immunoglobulins=== | ||
* Monoclonal gammopathy (IgA and/or IgG peak) | * Quantitative measurement of IgA, IgG, IgM (immunoglobulins) to look for immune paresis | ||
* Monoclonal gammopathy (IgA and/or IgG peak) is suggestive of multiple myeloma. | |||
* In multiple myeloma, the level of one type of immunoglobulin may be high while the others are low. | * In multiple myeloma, the level of one type of immunoglobulin may be high while the others are low. | ||
* Reverse in albumin:globulin ratio (low albumin, high globulin). | * Reverse in albumin:globulin ratio (low albumin, high globulin). | ||
Revision as of 19:23, 20 September 2015
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Laboratory findings consistent with the diagnosis of multiple myeloma include abnormal complete blood count, erythrocyte sedimentation rate (ESR), basic metabolic panel, electrophoresis and immunohistochemistry. An elevated concentration of serum protein without concomitant elevation of serum albumin level is very suggestive of multiple myeloma.
Laboratory Findings
Complete blood count
- The blood test result of patients with multiple myeloma may indicate pancytopenia.
- Decreased hemoglobin level is commonly seen.
- Elevated erythrocyte sedimentation rate.
Quantitative immunoglobulins
- Quantitative measurement of IgA, IgG, IgM (immunoglobulins) to look for immune paresis
- Monoclonal gammopathy (IgA and/or IgG peak) is suggestive of multiple myeloma.
- In multiple myeloma, the level of one type of immunoglobulin may be high while the others are low.
- Reverse in albumin:globulin ratio (low albumin, high globulin).
Basic metabolic panel
- Hypercalcemia due to increased osteoclasts activity.
- Raised serum creatinine due to reduced renal function.
- High serum protein (especially raised immunoglobulin) may prompt further testing
Electrophoresis
- Quantitative measurements of the paraprotein are necessary to establish a diagnosis and to monitor the disease.
- Protein electrophoresis of the blood and urine might show the presence of a paraprotein (monoclonal protein, or M protein) band, with or without reduction of the other types of immunoglobulins (known as immune paresis).
- One type of paraprotein is the Bence Jones protein which is a urinary paraprotein composed of free light chains.
- The paraprotein is an abnormal immunoglobulin produced by the tumor clone.
- Very rarely, the myeloma is nonsecretory (not producing immunoglobulins).
- In theory, multiple myeloma can produce all classes of immunoglobulin, but IgG paraproteins are most common, followed by IgA and IgM. IgD and IgE myeloma are very rare.
- In addition, light and or heavy chains (the building blocks of antibodies) may be secreted in isolation: κ- or λ-light chains or any of the five types of heavy chains (α-, γ-, δ-, ε- or μ-heavy chains).
Immunohistochemistry
- Staining particular cell types using antibodies against surface proteins) can detect plasma cells which express immunoglobulin in the cytoplasm but usually not on the surface; myeloma cells are typically CD56, CD38, CD138 positive and CD19 and CD45 negative. Cytogenetics may also be performed in myeloma for prognostic purposes.
- Other useful laboratory tests include quantitative measurement of IgA, IgG, IgM (immunoglobulins) to look for immune paresis, and β2-microglobulin which provides prognostic information. On peripheral blood smear the rouleaux formation of red blood cells is commonly seen.
- The recent introduction of a commercial immunoassay for measurement of free light chains potentially offers an improvement in monitoring disease progression and response to treatment, particularly where the paraprotein is difficult to measure accurately by electrophoresis (for example in light chain myeloma, or where the paraprotein level is very low). Initial research also suggests that measurement of free light chains may also be used, in conjunction with other markers, for assessment of the risk of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma.