Do you report an accurate international normalized ratio? Find out using local verification and calibration

Abstract

The current method for monitoring vitamin K antagonist (AVK) anticoagulant therapy is the international normalized ratio (INR) that provides consistency and standardization for the prothrombin time (PT) assay value. Even after the standardization of the INR, inaccuracies of this value have still been reported. To make the INR even more accurate, better local assessments of INR parameters are becoming available. These new methods use plasmas with certified INR values to locally verify and, if necessary, recalculate the international sensitivity index (ISI) for the local laboratory's reagent and instrument system. This CE Update will discuss the concepts of local verification and calibration to better define the manufacturer's assigned ISI value, thus reporting more accurate INR results.