How much does international normalized ratio monitoring cost during oral anticoagulation with a vitamin K antagonist? A systematic review.

Next-generation oral anticoagulants offer the potential for effective prevention and treatment of thrombosis without the need for repeated monitoring of the international normalized ratio (INR). This systematic review evaluated the costs associated with INR monitoring tests performed as part of the standard management of oral anticoagulation with vitamin K antagonists. Studies published in or after 1990 reporting the costs of INR monitoring were identified from bibliographic databases and manual searches of reference lists. Cost data were extracted and inflated to the year 2006 before purchasing power parity conversion to US dollars. A total of 29 studies reported the cost of one INR test, which was shown to range from $6.19 to $145.70. Cost estimates were based on various combinations of direct medical costs, such as healthcare contacts, equipment, laboratory tests, clerical costs (postage and stationery), telephone calls, quality control, training/education and patient transportation, and indirect costs, such as time lost from work. In conclusion, the cost of INR monitoring varied substantially between studies depending on the monitoring modality and setting, and the cost categories included. When selecting a published estimate, healthcare decision makers should ensure that the chosen estimate reflects local service provision as closely as possible.