title: Reliability of international normalised ratios from two point of care test systems: comparison with conventional methods.
abstract: OBJECTIVE
  To find out how accurately two point of care test systems--CoaguChek Mini and TAS PT-NC (RapidPointCoag)--display international normalised ratios (INRs).
  
  
  METHODS
  Comparison of the INRs from the two systems with a "true" INR on a conventional manual test from the same sample of blood.
  
  
  METHODS
  10 European Concerted Action on Anticoagulation centres.
  
  
  METHODS
  600 patients on long term dosage of warfarin.
  
  
  METHODS
  Comparable results between the different methods.
  
  
  RESULTS
  The mean displayed INR differed by 21.3% between the two point of care test monitoring systems. The INR on one system was 15.2% higher, on average, than the true INR, but on the other system the INR was 7.1% lower. The percentage difference between the mean displayed INR and the true INR at individual centres varied considerably with both systems.
  
  
  CONCLUSIONS
  Improved international sensitivity index calibration of point of care test monitors by their manufacturers is needed, and better methods of quality control of individual instruments by their users are also needed.
authors.affiliation: European Concerted Action on Anticoagulation Central Facility, School of Biological Sciences, University of Manchester, Manchester M13 9PT. ecaa@man.ac.uk
authors.forename: Leon
authors.initials: L
authors.lastname: Poller
authors.forename: Michelle
authors.initials: M
authors.lastname: Keown
authors.forename: Nikhil
authors.initials: N
authors.lastname: Chauhan
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: Caroline
authors.initials: C
authors.lastname: Shiach
authors.forename: Jorgen
authors.initials: J
authors.lastname: Jespersen
mesh_terms: D000925:Anticoagulants / Q000627:therapeutic use; D006801:Humans; D019934:International Normalized Ratio / Q000592:standards*; D019095:Point-of-Care Systems / Q000592:standards*; D012680:Sensitivity and Specificity; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014859:Warfarin