Validation of the Use of a Point-of-Care Device in Monitoring the International Normalised Ratio in Postoperative Cardiac Patients.
Dear Editor, Warfarin is prescribed for various conditions including mechanical heart valves, atrial fibrillation and venous thromboembolism. Prevention of bleeding and thromboembolic complications require maintenance in a tight therapeutic range. The use of patient self-testing has been well documented in the United Kingdom and Europe in prospective and retrospective studies.1-5 CoaguChek® XS (Roche Diagnostics, Basel, Switzerland) prothrombin coagulation monitoring system6,7 provides point-of-care (POC) monitoring with a measurement range of 0.8 to 8.0 international normalised ratio (INR) and consists of a CoaguChek® XS monitor and test strips. To date, validation studies have been limited to stable outpatient anticoagulation clinic cohorts,7 with studies done in cardiac patients perioperatively.8-10 However, these used arterial or whole blood samples and evaluated patients in the immediate perioperative period. Therefore, there is a void of data in the validity of such devices using capillary blood samples in cardiac patients during the recuperative in-hospital phase. The study aimed to validate the POC testing (POCT) device with capillary samples in an Asian cohort during the postoperative phase. By introducing the concept and validity of POC self-testing in patients, it would help to empower the patient to participate in his or her care, laying ground for developing an outpatient self-testing programme. The authors believe that this period is a window of opportunity for the implementation of self-POCT as patients are under closer supervision and more motivated.