Automated Multicapillary Electrophoresis for Analysis of Human Serum Proteins

Abstract

Abstract Background: We evaluated a new, automated multicapillary zone electrophoresis (CE) instrument (Capillarys®, 4.51 software version; Sebia) for human serum protein analysis. Methods: With the Capillarys β1-β2+® reagent set, proteins were separated at 7 kV for 4 min in 15.5 cm × 25 μm fused-silica capillaries (n = 8) at 35.5 °C in a pH 10 buffer with online detection at 200 nm. Serum samples with different electrophoretic patterns (n = 265) or potential interference (n = 69) were analyzed and compared with agarose gel electrophoresis (AGE; Hydrasys®-Hyrys®, Hydragel protein(e) 15/30® reagent set; Sebia). Results: CVs were <3.5% for albumin, <11% for α1-globulin, <4.1% for α2-globulin, <7.4% for β-globulin, and <5.8% for γ-globulin (3 control levels); measured throughput was 60 samples/h. In patients without paraprotein (n = 116), the median differences between CE and AGE were −5.4 g/L for albumin, 4.0 g/L for α1-globulin, 0.7 g/L for α2-globulin, 0.6 g/L for β-globulin (P <0.001 for all fractions), and −0.1 g/L for γ-globulin (not significant). More samples had at least one γ-migrating peak detected by CE (n = 135 vs 130; paraprotein detection limit, ∼0.5–0.7 g/L), but fewer were quantified (n = 84 vs 91) because of γ- to β-migration shifts. There was a 1.2 g/L median difference between CE and AGE for γ-migrating paraprotein quantification (n = 69; P <0.001). Several ultraviolet-absorbing substances (lipid emulsion, hemoglobin) or molecules (contrast agent, gelatin-based plasma substitute) induced CE artifacts. Conclusions:The Capillarys instrument is a reliable CE system for serum protein analysis, combining advantages of full automation (ease of use, bar-code identification, computer-assisted correction of α1-globulins) with high analytical performances and throughput.