Clinical Capillary Zone Electrophoresis of Serum Proteins: Balancing High Sensitivity and High Specificity

Capillary zone electrophoresis (CZE) is documented to have high sensitivity and specificity for the detection of monoclonal (M) proteins. In two large (>1500 participants) prospective studies in which CZE was compared with “immunofixation/immunoelectrophoresis”, the sensitivity of CZE was 95% (1)(2). This is superior to the sensitivity of agarose gel electrophoresis (AGE), which Katzmann et al. (1) found to be 91% and Meunier (3) found to be 92.2% (evaluation of 2060 sera containing an M-protein). Especially in the β-globulin region, CZE with Paragon CZE 2000 (Beckman-Coulter) is superior to AGE for detection of low-concentration M-proteins (IgA and light chains) (3)(4). The specificity of CZE is reported to be high (98.6%) and comparable to that of AGE (1)(5). In a prospective study (2), we described three M-proteins with high pI values that migrated in the slow γ region on AGE but were not detected with Paragon. In addition, one high-concentration IgG|gl with a pI ≈7 that migrated in the mid-γ region on AGE was not separated by CZE. The Paragon has recently been upgraded [modified buffer, higher voltage (10.3 kV), more efficient cooling, adapted software (1.6.02)], and according … [↵][1]bAuthor for correspondence. [1]: #xref-corresp-2-1