24 Resolution of Discrepant Results in Serum Protein Electrophoresis and Immunofixation Electrophoresis

• Published in: American journal of clinical pathology Vol. 149; no. suppl_1; p. S10
• Main Authors: Vick, Randol, Blakely, Katherine, Taylor, Sara, Han, Heping, Lewis, Sally
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 11.01.2018
• Subjects: Haptoglobin; Hemoglobin; Hemolysis; Proteins; Thrombin
• ISSN: 0002-9173; 1943-7722
• DOI: 10.1093/ajcp/aqx115.023

Abstract Introduction Serum protein electrophoresis (SPEP) from a 77-year-old male patient and a 33-year-old female patient showed an abnormal SPEP pattern with a M-spike in the beta region. The 77-year-old male patient had a 1 g/dL (17.6%) densitometer result in the beta fraction (normal range for beta fraction 0.6–1.3 g/dL) and the 33-year-old female patient had a 1.1 g/dL (14%) densitometer result in the beta fraction. These abnormal patterns were followed by an immunofixation electrophoresis (IFE), which did not reveal a distinctive monoclonal band in either patient. Methods Although neither patient’s samples appeared to show visible hemolysis, the samples were treated and incubated 1:1 with commercial thrombin reagent. Samples clotted after incubation with the thrombin, and a clot was removed from the sample. SPEP was repeated, and the initial M-spike in the beta region was not seen in the new SPEP. Conclusions A variety of other proteins besides monoclonal proteins may contaminate a serum protein electrophoresis sample. Hemolysis causes decreased alpha-2 band (haptoglobin), and appearance of a hemoglobin band between the alpha-2 and beta-1 regions. Treatment of the sample with thrombin prior to electrophoresis resulted in a normal SPEP pattern and resolution of the discrepancies, and eliminated the need for further unnecessary testing.