title: Validation of methods performance for routine biochemistry analytes at Cobas 6000 analyzer series module c501.
abstract: BACKGROUND
  Cobas 6000 (Roche, Germany) is biochemistry analyzer for spectrophotometric, immunoturbidimetric and ion-selective determination of biochemical analytes. Hereby we present analytical validation with emphasis on method performance judgment for routine operation.
  
  
  METHODS
  Validation was made for 30 analytes (metabolites, enzymes, trace elements, specific proteins and electrolytes). Research included determination of within-run (N = 20) and between-run imprecision (N = 30), inaccuracy (N = 30) and method comparison with routine analyzer (Beckman Coulter AU640) (N = 50). For validation of complete analytical process we calculated total error (TE). Results were judged according to quality specification criteria given by European Working Group.
  
  
  RESULTS
  Within-run imprecision CVs were all below 5% except for cholesterol, triglycerides, IgA and IgM. Between-run CVs for all analytes were below 10%. Analytes that did not meet the required specifications for imprecision were: total protein, albumin, calcium, sodium, chloride, immunoglobulins and HDL cholesterol. Analytes that did not fulfill requirements for inaccuracy were: total protein, calcium, sodium and chloride. Analytes that deviated from quality specifications for total error were: total protein, albumin, calcium, sodium, chloride and IgM. Passing-Bablok regression analysis provided linear equation and 95% confidence interval for intercept and slope. Complete accordance with routine analyzer Beckman Coulter AU640 showed small number of analytes. Other analytes showed small proportional and/or small constant difference and therefore need to be adjusted for routine operation.
  
  
  CONCLUSIONS
  Regarding low CV values, tested analyzer has satisfactory accuracy and precision and is extremely stable. Except for analytes that are coherent on both analyzers, some analytes require adjustments of slope and intercept for complete accordance.
authors.affiliation: Clinical Institute of Laboratory Diagnostics, Rijeka Clinical Hospital Center, Rijeka, Croatia. vesnasupak@gmail.com
authors.forename: Vesna
authors.initials: V
authors.lastname: Supak Smolcic
authors.forename: Lidija
authors.initials: L
authors.lastname: Bilic-Zulle
authors.forename: Elizabeta
authors.initials: E
authors.lastname: Fisic
mesh_terms: D001798:Blood Proteins / Q000032:analysis; D002624:Chemistry, Clinical / Q000295:instrumentation / Q000379:methods; D008076:Cholesterol, HDL / Q000097:blood; D004573:Electrolytes / Q000097:blood; D004798:Enzymes / Q000097:blood; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D015203:Reproducibility of Results; D014131:Trace Elements / Q000097:blood; D014280:Triglycerides / Q000097:blood
chemical_list: D001798:Blood Proteins; D008076:Cholesterol, HDL; D004573:Electrolytes; D004798:Enzymes; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D014131:Trace Elements; D014280:Triglycerides