Performance Evaluation of the Coag-Sense Prothrombin Time (PT)/INR Monitoring System

Introduction
Oral anticoagulant therapy (OAT) using warfarin (Coumadin) has surged in recent years due to an increased number of indications and its demonstrated effectiveness. The primary means of monitoring the response to warfarin is the Prothrombin Time (PT) test, which is measured in seconds. The increased use of OAT has led to the development of point-of-care (POC) portable monitoring devices designed to use a capillary sample of whole blood for PT determination.

Prothrombin time test results can vary widely depending on the method of clot detection and the thromboplastin reagent used. For that reason the World Health Organization (WHO), in conjunction with the International Committee for Standardization in Haematology and the International Committee on Thrombosis and Haemostasis (ICSH/ICTH), developed a measure of coagulation called the International Normalized Ratio (INR). The INR is a mathematical calculation that corrects for the variable sensitivities of thromboplastin reagents.