title: Quality assessment of CoaguChek point-of-care prothrombin time monitors: comparison of the European community-approved procedure and conventional external quality assessment.
abstract: BACKGROUND
  There is a need for dependable quality assessment (QA) of the widely used CoaguChek point-of-care testing prothrombin time monitor. By use of the prescribed set of 5 CoaguChek certified international normalized ratio (INR) QA plasmas, we compared the reliability of the immediate QA of individual monitors described in the European Community-recommended Technology Implementation Plan with conventional external QA analysis.
  
  
  METHODS
  Experienced staff tested CoaguChek point-of-care monitors in routine use for controlling oral anticoagulant dosage at 9 Netherlands Thrombosis Service Centres. Testing was performed with both the certified CoaguChek INR for a set of 5 QA individual plasmas from the Eur Con Action on Anticoag (ECAA) and conventional external QA analysis.
  
  
  RESULTS
  Patients brought 523 CoaguChek monitors to our service centers for assessment. The proportion with unsatisfactory performance indicated by a 15% deviation from the ECAA set was compared with 15% deviation from overall median INR of all CoaguChek monitors in the survey, as in conventional QA analysis. The results were similar (20.3% and 18.5%, respectively). Interlot differences of CoaguChek test strips were detected, but the incidence of unsatisfactory performance was similar with both analyses, from 6.5% to 37.5% with the certified INR method and from 5.9% to 33.3% with the overall median analysis.
  
  
  CONCLUSIONS
  The results validate the use of the European Action on Anticoagulation rapid single-instrument QA-specific procedure for CoaguChek users compared with the nonspecific conventional QA analysis that relies on deviation from the overall median INR.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom. ecaa@manchester.ac.uk
authors.forename: Leon
authors.initials: L
authors.lastname: Poller
authors.forename: Michelle
authors.initials: M
authors.lastname: Keown
authors.forename: Saied A
authors.initials: SA
authors.lastname: Ibrahim
authors.forename: Felix J M
authors.initials: FJ
authors.lastname: van der Meer
authors.forename: Anton M H P
authors.initials: AM
authors.lastname: van den Besselaar
authors.forename: Armando
authors.initials: A
authors.lastname: Tripodi
authors.forename: Jørgen
authors.initials: J
authors.lastname: Jespersen
authors.forename: Pieter
authors.initials: P
authors.lastname: Meijer
authors.forename: Cornelis
authors.initials: C
authors.lastname: Kluft
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use; D016903:Drug Monitoring / Q000295:instrumentation; D005062:European Union; D006801:Humans; D019934:International Normalized Ratio; D019095:Point-of-Care Systems; D011517:Prothrombin Time / Q000295:instrumentation*; D011786:Quality Control; D015203:Reproducibility of Results
chemical_list: D000925:Anticoagulants