From the Guidelines
Abnormal serum protein electrophoresis (SPEP) results can be caused by various conditions, with the most concerning being multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), amyloidosis, and other plasma cell disorders that produce abnormal immunoglobulins, as reported in the most recent study 1.
Causes of Abnormal SPEP
The causes of abnormal SPEP results include:
- Multiple myeloma
- Monoclonal gammopathy of undetermined significance (MGUS)
- Amyloidosis
- Other plasma cell disorders
- Chronic infections
- Inflammatory conditions like rheumatoid arthritis or lupus
- Liver diseases such as cirrhosis or hepatitis
- Kidney diseases including nephrotic syndrome
- Certain cancers like lymphoma
Diagnostic Approach
When an abnormal SPEP is found, further testing is typically needed, including:
- Immunofixation electrophoresis
- Free light chain assay
- Complete blood count
- Comprehensive metabolic panel
- Possibly bone marrow biopsy depending on the specific abnormality The pattern of protein abnormalities helps determine the underlying cause, with different conditions showing characteristic changes in specific protein fractions, as noted in 2, 3, 4, 5, 6, 7.
Key Considerations
It is essential to use the same test for serial studies to ensure accurate relative quantification, as stated in 2. Additionally, the serum free light chain (FLC) assay is useful in monitoring disease response and progression in patients with non-secretory myeloma, as mentioned in 2.
From the Research
Causes of Abnormal Serum Protein Electrophoresis (SPEP)
Abnormal SPEP results can be caused by various conditions, including:
- Monoclonal gammopathies, which are associated with a clonal process that is malignant or potentially malignant, such as multiple myeloma, Waldenström's macroglobulinemia, and solitary plasmacytoma 8
- Polyclonal gammopathies, which may be caused by any reactive or inflammatory process 8
- Acute inflammation, malignancy, trauma, necrosis, infarction, burns, and chemical injury, which can cause changes in plasma protein levels 8
- Autologous stem cell transplantation (ASCT), which can lead to the development of oligoclonal patterns in SPEP results 9
- Lymphoplasmacytic lymphoma, such as Waldenström's macroglobulinemia, which is characterized by the presence of IgM monoclonal protein 10
Specific Conditions Associated with Abnormal SPEP
Some specific conditions that can cause abnormal SPEP results include:
- Multiple myeloma, which is characterized by a homogeneous spike-like peak in a focal region of the gamma-globulin zone 8
- Waldenström's macroglobulinemia, which is characterized by the presence of IgM monoclonal protein and clonal lymphoplasmacytic cells in bone marrow 10
- Plasma cell myeloma, which can lead to the development of oligoclonal patterns in SPEP results after ASCT 9
- Chronic lymphocytic leukemia, which can have similar gene expression patterns to Waldenström's macroglobulinemia 11