Interference and failure: The challenge of high-concentration IgM monoclonal protein in capillary zone electrophoresis.

作者：Yanhua Zhao, Minjie Zhang, Wei Gan · 发表于：Clinical Biochemistry · 年份：2026 · DOI：10.1016/j.clinbiochem.2026.111099 · 研究领域：Medicine

BACKGROUND Capillary zone electrophoresis (CZE) is a standard method for serum protein separation, but its performance can be compromised by IgM monoclonal proteins, leading to false-negative results. METHODS We report a case of Waldenström macroglobulinemia (IgM 56.05 g/L) with repeated CZE failure. Immunofixation electrophoresis (IFE) confirmed an IgM kappa monoclonal protein. Four pretreatment protocols were evaluated: 1) 37°C incubation; 2) dilution with distilled water; 3) dilution with 0.9% saline; and 4) pretreatment with β‑mercaptoethanol (BME). Gel-based serum protein electrophoresis (SPE) and immunosubtraction CZE were also performed to investigate the interference mechanism. RESULTS Initial CZE failed to yield an interpretable electrophoretogram. Incubation at 37°C showed no improvement. Dilution with distilled water induced visible precipitation and resulted in a false-negative electrophoretic pattern with a marked drop in measured total protein. Dilution with saline prevented precipitation but still failed to reveal a distinct monoclonal spike, despite biochemical measurements consistent with high globulin levels. In contrast, pretreatment with BME successfully restored a clear monoclonal spike in the β‑γ region on CZE, demonstrating restored solubility and proper migration. IFE corroborated the presence of the IgM kappa monoclonal protein. Gel-based SPE successfully showed a distinct M-protein band without interference, while immunosubtraction CZE failed und...