The International Normalized Ratio (INR) is designed to standardize the reporting of prothrombin time (Pl) measurements in patients taking warfarin. To appropriately manage patients taking anticoagulants, a delicate balance must be achieved between too much or too little anticoagulation, which can respectively result in bleeding or hemorrhage. Variability and bias in INR determinations leads to errors in therapeutic management. Quantitative estimates of the magnitude of such errors have heretofore been unavailable. Using advanced probabilistic models for the International Normalized Ratio (INR), we will design, test, and build COAGSa Computer- based Oral Anticoagulant Guidance System running under Windows to help clinicians and laboratories explore the complexities of oral and coagulation. COAGS will be a set of user-friendly tools to assist laboratories in analyzing their own data, conducting reference mean studies, probing the implications of quality control performance on the INR and clinical decisions, conducting comparison studies with other laboratories, providing information to clinicians about the precision of INR data, and comparing different instruments/reagents to one another to decide which is optimal for a particular laboratory setting and patient population.We will test the algorithms and evaluate the utility of the approach in three laboratory settings during Phase I. COAGS will enable users to perform sophisticated mathematical operations that realistically model the complexities inherent in oral anticoagulant monitoring and to make sound decisions based on the best data available. The Phase II product will build on the results of the Phase I research. The outgrowth of this work will be an improvement in patient outcomes due to better anticoagulant management decisions.National Heart, Lung, and Blood Institute (NHLBI)
