The abnormal serum protein electrophoresis findings in this patient had no impact on her unfortunate rapid death, and the correct (or incorrect) identification of the abnormal fraction did not impact treatment. The detection of this electrophoretic abnormality, however, reinforces the need for cautious interpretation of serum and urine protein electrophoresis patterns.
A number of “classic” serum electrophoresis patterns require further confirmatory tests for diagnosis. Absence of an α-1 band, for example, suggests A1AT deficiency disease; polyclonal elevation of the γ fraction suggests autoimmune, infectious, or liver disease; decreased albumin and increased α-2 fractions suggest nephrotic disease; and an additional discrete band suggests monoclonal gammopathy. The diagnosis of monoclonal gammopathy is usually confirmed by immunofixation electrophoresis. The most common serum electrophoretic abnormalities that are detected on agarose gels and are confused with monoclonal gammopathies are fibrinogen (due to incomplete blood clotting) and hemoglobin (due to hemolysis). The ultraviolet detection systems used in capillary electrophoresis have additional interferences that must be recognized (e.g., radioopaque imaging agents as well as some antibiotics). Initial diagnostic observations of abnormal electrophoretic bands must therefore be confirmed by immunotyping of heavy and light chain isotype.
Serum protein electrophoretic abnormalities that are monoclonal proteins may represent significant disease and should be pursued to define the specific plasma proliferative disease that is leading to the secretion of the monoclonal immunoglobulin. In addition, abnormalities, such as in this case, in which there is no monoclonal gammopathy should not be ignored and may provide insights into the disease.
Grant/Funding Support: National Cancer Institute CA 107476 and CA 62242.
Financial Disclosures: None declared.
- © 2008 The American Association for Clinical Chemistry