ABSTRACT

Prothrombin time (PT) is used universally for the laboratory control of oral anticoagulant treatment. Since the results show important variability due to tromboplastin and instruments used it is recommended that the PT ratio be transformed to the International Normalized Ratio ([NR). Use of the INR should make it possible to more safely and effectively treat patients at risk for thrombosis by enabling the physician to make a direct comparison.

Keywords: Prothrombin Time (PT), International Normalized Ratio ([NR)