title: The importance of having a flexible scope ISO 15189 accreditation and quality specifications based on biological variation--the case of validation of the biochemistry analyzer Dimension Vista.
abstract: BACKGROUND
  Technological innovation requires the laboratories to ensure that modifications or incorporations of new techniques do not alter the quality of their results. In an ISO 15189 accredited laboratory, flexible scope accreditation facilitates the inclusion of these changes prior to accreditation body evaluation. A strategy to perform the validation of a biochemistry analyzer in an accredited laboratory having a flexible scope is shown.
  
  
  METHODS
  A validation procedure including the evaluation of imprecision and bias of two Dimension Vista analysers 1500 was conducted. Comparability of patient results between one of them and the lately replaced Dimension RxL Max was evaluated. All studies followed the respective Clinical and Laboratory Standards Institute (CLSI) protocols. 30 chemistry assays were studied. Coefficients of variation, percent bias and total error were calculated for all tests and biological variation was considered as acceptance criteria. Quality control material and patient samples were used as test materials. Interchangeability of the results was established by processing forty patients' samples in both devices.
  
  
  RESULTS
  27 of the 30 studied parameters met allowable performance criteria. Sodium, chloride and magnesium did not fulfil acceptance criteria. Evidence of interchangeability of patient results was obtained for all parameters except magnesium, NT-proBNP, cTroponin I and C-reactive protein.
  
  
  CONCLUSIONS
  A laboratory having a well structured and documented validation procedure can opt to get a flexible scope of accreditation. In addition, performing these activities prior to use on patient samples may evidence technical issues which must be corrected to minimize their impact on patient results.
authors: Emergency Laboratory, Department of Laboratory Medicine, Hospital Universitario La Paz, Madrid, Spain. pfernandez.hulp@gmail.com
authors: Pilar
authors: P
authors: Fernandez-Calle
authors: Sandra
authors: S
authors: Pelaz
authors: Paloma
authors: P
authors: Oliver
authors: Maria Jose
authors: MJ
authors: Alcaide
authors: Ruben
authors: R
authors: Gomez-Rioja
authors: Antonio
authors: A
authors: Buno
authors: Jose Manuel
authors: JM
authors: Iturzaeta
mesh_terms: D000068:Accreditation / Q000592:standards*; D015415:Biomarkers / Q000097:blood; D006801:Humans; D062069:Inventions / Q000592:standards*; D007755:Laboratories, Hospital / Q000592:standards*; D011786:Quality Control; D062606:Tertiary Care Centers; D054928:Validation Studies as Topic
chemical_list: D015415:Biomarkers