Should we trust INR testing?

  We read with interest the recent BMJ editorial “Rivaroxaban:Can we trust the evidence”.1 which questions the conclusions from the ROCKET AF clinical trial on Rivaroxaban 2. Cohen raises questions about the accuracy of the INRs used for monitoring patients in the warfarin control arm and suggests that they may have compromised the validity of the published conclusions. The ROCKET investigators have defended their conclusions after re assessing the data in light of these concerns 3. The device used for INR testing in the warfarin control arm was not identified in the original publication but subsequently has been revealed as the INRatio Point of Care (POC) device. This device was the subject of a safety recall notice by FDA in 2014 due to “clinically significantly lower” readings compared to laboratory values, with the fault going back to 2002 (before the Rocket AF trial started). The BMJ editorial points out that a falsely low INR reading could mean that patients in the control arm may have had their warfarin dose unnecessarily increased leading to a greater risk of bleeding. To ensure accuracy, POC INR testing should be subjected to the same level of quality control (QC) and quality management systems that laboratory INR testing has to meet. Appropriate and effective External Quality Assessment (EQA) for POC INR testing devices is possible 4 and there has been a POC INR EQA programme available in the UK for 20 years. In the UK NEQAS for B...
Source: Doc2Doc BMJ Cardiology - Category: Cardiology Authors: Source Type: forums