A message from Crystal Azevedo, Eastern Maine Medical Center:
Hello George, I have a question regarding the new Xa inhibitors and dabigatran and point of care (POC) systems. Is there any known interference in the prothrombin time/international normalized ratio (PT/INR) determination of POC assays when a patient is on one of these medications? We are using the iSTAT system on our ED patients and we see the population on these medications growing rapidly. Thanks!
Hi, Crystal, and thanks for your question. I’m sorry to say I don’t have a short answer regarding POC assays for the new oral anticoagulants dabigatran (a direct thrombin inhibitor), rivaroxaban (direct Xa inhibitor) or apixaban (also a direct Xa inhibitor). So far, everything I’ve seen or participated in has been geared toward central laboratory assays.Dave McGlasson and I just published a Focus series in the Winter, 2013 issue of Clinical Laboratory Science; Anticoagulant Therapy, available at www.ascls.org, that reviews all the current and developing laboratory assays, and there is also a recent comprehensive review article, Garcia D, Barrett YC, Ramacciotti E, Weitz JI. Laboratory assessment of the anticoagulant effect of the next generation of oral anticoagulants. J Thromb Haemostas 2013; 11: 245–52. Take a look also at an April 2 post from Linda Stang on the affects of apixaban on clot-based assays.
All of the new oral anticoagulants prolong the PT/INR, so there is some sentiment in favor of standardizing the PT for these new drugs, which leads me to think that the POC instrument manufacturers are probably scrambling to find ways to validate their instruments for this purpose as well. Perhaps one of our subscribers has some information on this, but meanwhile, let’s see what Abbott, Roche, ITC, and the others are cooking up.