Emerg Med J 28:136-140 doi:10.1136/emj.2009.086520
  • Original article

Comparison of emergency department point-of-care international normalised ratio (INR) testing with laboratory-based testing

  1. Kirsty Skinner1
  1. 1Emergency Department, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
  2. 2Discipline of Emergency Medicine, University of Western Australia, Crawley, Western Australia, Australia
  1. Correspondence to Professor Antonio Celenza, Emergency Medicine, Level 2, R Block, QE II Medical Centre, Nedlands 6009, Western Australia, Australia; tony.celenza{at}
  1. Contributors Both authors contributed to the study concept and design, acquisition of data, drafting, review and final approval of manuscript. KS also provided study coordination and data entry. AC also provided statistical analysis and critical revisions.

  • Accepted 10 February 2010
  • Published Online First 29 May 2010


Background Bedside international normalised ratio (INR) testing in emergency departments (ED) to assess for coagulopathies has not previously been examined.

Objectives To compare point-of-care INR (POCINR) testing in an ED with laboratory-based results (LABINR) using a prospective observational cohort study.

Methods Prospectively recruited patients requiring laboratory INR testing had simultaneous POC testing using a CoaguChek XS Plus in an urban tertiary hospital ED. Clinicians were blinded to the POC result and clinical decisions were based on the laboratory result. Result agreement was considered a priori to be a POCINR result within 15% of the laboratory result. Secondary outcomes included potentially incorrect management if POCINR had been used as the diagnostic test.

Results Two hundred and ninety-three patients were included. Agreement within a 15% range occurred in 245 patients (83.6% (95% CI 78.9% to 87.4%)). Following independent medical record review by the authors, no patients with POCINR agreement within a 30% range of LABINR would have had changes in management. Eleven patients had POCINR results which may have resulted in significant changes to management. Ten patients were incorrectly identified by the POCINR as having a clinically significant coagulopathy not confirmed by the LABINR result, which may have resulted in inappropriate management. One patient with snake venom-induced coagulopathy had a normal POCINR (1.4). No other patients with a normal POCINR had a clinically significant coagulopathy.

Conclusions POCINR testing can exclude clinically significant coagulopathy in the ED. LABINR is required to confirm non-normal INR results, particularly in the supratherapeutic range.


  • Funding The CoaguCheck machine was supplied by another department within the hospital for the purposes of the study. Consumables were purchased from departmental funds. No manufacturer support or contact occurred.

  • Competing interests None.

  • Ethical approval Ethics approval was obtained from the hospital's human research ethics committee with waiver of patient consent allowable due to the minimal risk of the intervention.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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