Accuracy and clinical usefulness of the near-patient testing CoaguChek S international normalised ratio monitor in rural medical practice

Objective: To compare the accuracy and clinical usefulness of the near‐patient testing CoaguChek S INR monitor in rural medical practice. Design, setting and main outcome measures: General practices were identified through Australian university departments of rural health. Study investigators trained general practitioners and/or practice nurses in the use of the CoaguChek S INR monitor. General practices obtained a fingerprick sample for testing with the INR monitor to compare with conventional pathology testing for accuracy. An evaluation questionnaire was administered to users of the machine to assess ease of use and clinical usefulness. Results: A total of 169 patients from 15 general practice sites provided 401 paired (CoaguChek S and laboratory) INR results. The CoaguChek S was found to be accurate when compared to laboratory INR ( r = 0.89), despite complicating variables such as multiple users of the monitor and multiple laboratories used for comparison with the CoaguChek S INR. Overall, 88% of dual INR measurements were within 0.5 INR units of each other. For laboratory INR ≤ 1.9, 2.0–3.5 and ≥ 3.6, 97%, 90% and 57% of readings were within 0.5 INR units, respectively. Clinical agreement occurred 93% and 90% of the time against published expanded and narrow criteria, respectively. Conclusions: The routine use of near‐patient testing, with appropriate training and quality assurance programs, has the potential to increase the safety and efficacy of warfarin therapy in rural and remote communities. What is already known on this subject? : There is clear evidence of the under use of warfarin in patients with atrial fibrillation (AF) and the under‐use is greatest in rural areas. One of the barriers to the use of warfarin in these areas is the relative lack of access to pathology services for regular international normalised ratio (INR) testing What does this study add? : This study demonstrates that the performance of the CoaguChek S INR monitor in the rural general practice setting was excellent. Our results indicate that the CoaguChek S INR monitor has the potential to lead to safer and more effective use of warfarin and therefore to better management of anticoagulated patients in rural and remote areas