Confronto tra due sistemi per elettroforesi capillare e in gel d’agarosio per la ricerca e caratterizzazione di componenti monoclonali nel siero

Comparison of capillary and agarose gel electrophoresis for the identification and characterization of monoclonal immunoglobulins. The aim of this study was to compare the performance of two systems for agarose gel (AGE) and capillary (CZE) serum protein electrophoresis (SAS3/4/5 Alfa Wassermann and Paragon CZE 2000 Beckman Coulter) for the detection and characterization of monoclonal immunoglobulins (M proteins). Two independent persons reviewed 960 consecutively ordered serum protein electrophoresis patterns, 79 (8.2%) of which showed one or more M proteins at immunofixation. For M protein detection, we found similar sensitivities for AGE and CZE (89.9% vs. 94.9%, P = 0.368), with AGE showing high specificity than CZE (99.3% vs. 96.3%, P <0.0001). With regards to M protein characterization, performed on a series of 41 consecutive samples (25 of which positive for M proteins), agreement between methods was 97.6%. A good correlation (r2 = 0.947) was found when the two methods were compared for M protein quantitation (n = 180), even if a more pronounced bias was noted with M protein concentrations >25 g/L. In agreement with previously published studies, we conclude that both AGE and CZE techniques can be used in clinical laboratories for M protein detection and characterization, even if the detection specificity of AGE as a screening test is higher.