Practicability of patient self-testing of oral anticoagulant therapy by the international normalized ratio (INR) using a portable whole blood monitor. A pilot investigation

The prophylactic efficacy of long-term oral anticoagulant treatment (OAT) has been demonstrated in a number of clinical conditions with increased tendency to thromboembolism, and the number of individuals subjected to OAT in the industrialised world has increased substantially in recent years. Since this therapy requires considerable resources from both the health care system and the patients, the feasibility of patients' self-monitoring and self-management of OAT has been investigated (1,2,3). The anticipated advantages of this approach include improved convenience and compliance for the patient, who may increase his apprehension for managing the treatment. In addition, self-testing allows for more frequent control compared to the conventional out-patient approach. Importantly, a prerequisite for conceiving a safe and operational concept for patient self-management (PSM) is the availability of a portable INR monitoring system with an accuracy, precision, reproducibility, and long-term reliability comparable to standard coagulometric equipment. The purpose of the present study was to evaluate the feasibility of a commercially available INR-monitor, CoaguChek(R), for patient self-testing, through a step-wise investigation of the performance characteristics of the equipment in the laboratory, in command of the patient, and during self-testing and self-adjustment of treatment at home. Laboratory INR values were used as reference.