Coupling proteinemia and serum protein electrophoresis: evaluation of the capillary technique (Capillarys 2, Sebia), experience from Clermont-Ferrand

Serum protein electrophoresis (SPE) is a routine analysis that requires to quantify the total serum proteins in order to calculate the concentration in g/L of each electrophoretic protein fraction. Aim of this study was to evaluate the performances of the "Capillarys Total protein" kit (Sebia (R)), coupled to the Capillarys 2 system (Sebia (R)), allowing the proteinemia quantification by capillary electrophoresis (EC) simultaneously to the electrophoretic separation. We compared the proteinemia analyzed in EC with the spectrophotometric reference technique for 904 serums. Our results validated the performances of this kit used on the Capillarys 2 system. We noticed interferences identified for 5.8% of total serums: serums with strong monoclonal immunoglobulinemia (proteinemia of 0 g/L), with inconsistent electrophoretic profile (proteinemia not calculated), and lipemic serums (discordant proteinemia). After exclusion of the lipemic serums or serums without proteinemia associated to the EC profile, a good correlation was found for these 94.2% serums analyzed in EC (r = 0.93) in comparison with the reference technique. Then, the kit developed by Sebia (R) to perform SPE coupled to proteinemia analysis is usable in routine analysis except for the lipemic serums and for the serum with intense monoclonal immunoglobulinemia. Advantage of such a coupling is to better organize the unit specifically implicated in proteins exploration. But this technique is longer, leading to slowing EC analyses. Taking in account these limitations and restrictions, and in view of the development of complete pre-analytical chains in hospital labs, this technique, despite its performance, was not retained by Sebia (R) for future commercialization.