title: Comparison between ADVIA Chemistry systems Enzymatic Creatinine_2 method and ADVIA Chemistry systems Creatinine method (kinetic Jaffe method) for determining creatinine.
abstract: OBJECTIVE
  The aim of this study was two-fold: Firstly, to compare the serum creatinine concentration measured by enzymatic method and uncompensated kinetic Jaffe method, and secondly, to compare the effects of certain interfering substances such as glucose, bilirubin, proteins, triglycerides and hemoglobin on creatinine measurement.
  
  
  METHODS
  The determination of serum creatinine concentrations by enzymatic method and uncompensated kinetic Jaffe method was performed on ADVIA® 2400 analyzer. The interfering substances were tested by adding solutions of interference to serum pool with low (62 μmol/L), medium (221 μmol/L) and elevated (486 μmol/L) creatinine concentration.
  
  
  RESULTS
  In the method comparison study, despite the fact that the correlation between both methods for determining serum creatinine is very good (r = 0.998, p < 0.001), the regression analysis revealed that the results are not transferable, as indicated by the slope and intercept, which are significantly different from 1 and 0, respectively. A positive bias of + 14.1% in the determination of serum creatinine by uncompensated kinetic Jaffe method was found, and when the creatinine value is lower than ∼ 180 μmol/L this difference or bis progressively increases. We found a significant positive interference due to proteins and glucose and a significant negative interference due to bilirubin by kinetic Jaffe method, and no interferences by enzymatic method were found.
  
  
  CONCLUSIONS
  In conclusion, the enzymatic method is the best choice for determining serum creatinine with the ADVIA® 2400 analyzer.
authors.affiliation: Servicio de Análisis Clínicos, Área Sanitaria de Ferrol , Ferrol, A Coruña , Spain.
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Hermida
authors.forename: María J
authors.initials: MJ
authors.lastname: Lorenzo
authors.forename: Aida
authors.initials: A
authors.lastname: Pérez
authors.forename: María
authors.initials: M
authors.lastname: Fernández
authors.forename: Olatz
authors.initials: O
authors.lastname: Sagastagoia
authors.forename: Concepción
authors.initials: C
authors.lastname: Magadán
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001663:Bilirubin / Q000097:blood; D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards; D001786:Blood Glucose; D001798:Blood Proteins / Q000032:analysis / Q000737:chemistry; D003404:Creatinine / Q000097:blood*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D012044:Regression Analysis
chemical_list: D001786:Blood Glucose; D001798:Blood Proteins; D003404:Creatinine; D001663:Bilirubin
keywords: Creatinine; analytical performance; enzymatic method; interfering substances; kinetic Jaffe method