Should you use gel or capillary serum protein electrophoresis to monitor myeloma

Laboratory professionals play a key role in diagnosing and managing multiple myeloma, the second most common blood cancer and the most common form of plasma cell dyscrasia. According to the American Cancer Society, an estimated 36,110 people will be diagnosed with multiple myeloma in the U.S. in 2025, and 12,030 Americans will die with the disease (1).

The laboratory helps clinicians manage plasma cell dyscrasia by testing proteins via electrophoresis and other methodologies. Numerous medical groups, including the International Myeloma Working Group (IMWG), the College of American Pathologists (CAP), and the National Comprehensive Cancer Network (NCCN), recommend using serum protein electrophoresis (SPEP) and immunofixation electrophoresis (IFE), along with serum free light chains, for this purpose (2-4).

Agarose gel electrophoresis has been considered the gold standard for SPEP and IFE for some time now, with progress made over the years to increase laboratory efficiencies and lower the costs associated with these techniques.

Recent advances suggest that an electrophoretic method for interrogating serum proteins in a thin capillary tube may now be a viable alternative to the gel approach. Capillary electrophoresis technology appeared on the market in the late 1990s to interrogate serum proteins in plasma cell dyscrasia.

However, the capillary method still has not been widely adopted within clinical laboratories. According to one 2018 study, fewer than 32% of labs surveyed worldwide used capillary electrophoresis for diagnosing and monitoring plasma cell dyscrasia; the remainder used agarose gel electrophoresis (5).

Potential impact on the laboratory

Although lab leaders are generally familiar with the benefits of gel electrophoresis, they should also be aware of the potential positive impact that capillary electrophoresis could have on their laboratory. Research suggests that this method could improve efficiencies and lower costs compared to gel electrophoresis, while maintaining quality results.

One of the largest benefits of capillary electrophoresis over agarose gel electrophoresis is the time it saves the scientists who perform testing at the bench. Because agarose methods require a large degree of hands-on manipulation, they cost the laboratory more staff time (as measured in full-time equivalent hours) than capillary methods, which are far less labor-intensive.

Current points of contention with the capillary method

Much of the data in the literature points toward capillary methods being less sensitive than gel methods, especially with regard to specific immunoglobulins or light chains. That said, little data has been published within the past 5 years that evaluates the most recent agarose gel and capillary electrophoresis technologies.

While the lack of recent data is not ideal, it should not be viewed as a deterrent. A close inspection of the literature shows that, although there are certain aspects of the capillary technique that are less sensitive than comparable components of gel preparation, capillary methodology shows similar sensitivity and specificity to agarose gel electrophoresis when evaluated as a complete method.

One of the most critical parts of the electrophoresis testing process is the interpretation of the electrophoretogram. As with any piece of laboratory testing, ensuring that lab professionals receive appropriate education and training is paramount to achieving the highest quality results. Such staff instruction is lacking in most of the published comparison studies.

Research suggests that, when proper education and training are employed, interpretations improve across the board, allowing for capillary electrophoresis to have results that are as high quality as those achieved with agarose gel electrophoresis.

Eric A. Walradth, MA, MLS(ASCP)^CM SH^CM, is the director of laboratory services at Hematology-Oncology Associates of CNY. +Email: [email protected]

References

1. American Cancer Society. Key statistics about multiple myeloma. https://www.cancer.org/cancer/types/multiple-myeloma/about/key-statistics.html (Accessed February 2025).
2. College of American Pathologists. Laboratory detection and initial diagnosis of monoclonal gammopathies statements and strengths of recommendations. https://www.cap.org/protocols-and-guidelines/cap-guidelines/current-cap-guidelines/laboratory-detection-initial-diagnosis-monoclonal-gammopathies (Accessed February 2024).
3. Rajkumar SV, Dimopoulos MA, Palumbo A, et al. International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma. Lancet Oncol 2014; doi:10.1016/S1470-2045(14)70442-5.
4. National Comprehensive Cancer Network. NCCN clinical practice guidelines in oncology: Multiple myeloma. https://www.nccn.org/professionals/physician_gls/pdf/myeloma.pdf (Accessed March 2024).
5. Genzen JR, Murray DL, Abel G, et al. Screening and diagnosis of monoclonal gammopathies: An international survey of laboratory practice. Arch Pathol Lab Med 2018; doi:10.5858/arpa.2017-0128-CP.