title: Precision and long-term stability of capillary electrophoresis measurement of serum protein zones.
abstract: BACKGROUND
  Analytical evaluations of an available system for capillary zone electrophoresis (CZE) of serum protein have been reported. However, data concerning long-term precision and stability of the system, operated under routine conditions, are lacking. We report data from an internal quality control (QC) scheme, obtained over a 1-year period.
  
  
  METHODS
  Measurements were done with a pair of instruments (Beckman Paragon CZE 2000 system), each equipped with seven capillaries. After preliminary (1 month) assessment of possible inter-capillary and inter-instrument variations, the QC material (a home prepared serum pool stored in the frozen state) was assayed daily over a 1-year period.
  
  
  RESULTS
  Maximum inter-capillary and inter-instrument differences were 3.1% and 2.4%. No significant trend was observed for daily values (205 measurements over 1 year); in the same period overall imprecision values (CV) were in the interval 1.2% (albumin) to 3.2-6.1% (globulin zones). Mean monthly imprecision (CV) values were in the interval 1.1% (albumin) to 5.2% (globulin zones). There was no significant trend of monthly means with time. The observed imprecision values were within the biological variation-derived goals for imprecision.
  
  
  CONCLUSIONS
  It is concluded that the assessed analytical instruments, operated in routine conditions, show long-term stability and imprecision consistent with the clinical use of the results produced.
authors.affiliation: Laboratorio di Chimica Clinica, Ospedale L. Sacco, Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Luraschi
authors.forename: Simona
authors.initials: S
authors.lastname: Brambilla
authors.forename: Ilenia
authors.initials: I
authors.lastname: Infusino
authors.forename: Carlo
authors.initials: C
authors.lastname: Franzini
mesh_terms: D001798:Blood Proteins / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D011786:Quality Control; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D001798:Blood Proteins