From Meg Harlin, Peninsula Regional Medical Center in Maryland: Our Laboratory will be bringing in new coagulation analyzers from Instrumentation Laboratories, Inc.; TOPS 300, in February, 2014. We currently perform prothrombin time and international normalized ratio (PT/ INR), partial thromboplastin time (APTT, PTT), fibrinogen, and D-dimer. A Few years ago we stopped doing bleeding times, mixing studies and circulating inhibitors when the lab became a lean core. We are a trauma center, and also do a lot of cardiac and orthopedics. We do have the VerifyNow for platelet function for anti-P2Y12 agents and aspirin. Do you think it would be beneficial if we started thrombin times (TT) and anti-Xa’s at this point of starting up new instrumentation? Thank you for your time with my question, I look forward to hearing from you.
Hello, Meg, and thank you for your question, one that I am sure is asked by many coagulation lab supervisors. Yes, you will need TTs, demand for which has risen as more and more patients are taking the direct thrombin inhibitor dabigatran (Pradaxa), which can be ruled out by a normal TT, and ruled in, though not quantified, by a prolonged TT. We are likely to be measuring dabigatran using the newly developed plasma-diluted thrombin time as soon as it is FDA-cleared, so that would be another reason for setting up the basic TT.
Also, the anti-Xa, in addition to being a more valid assay than PTT for unfractionated heparin, which is used often in cardiology, is essential for low molecular weight heparin, fondaparinux, and now the new target-specific oral anti-Xa anticoagulants rivaroxaban (Xarelto) and apixaban (Eliquis), with edoxaban to follow soon. I predict the demand will be high.
Finally, you may want to convince your financial folks that mixing studies are also cost-effective as a means for finding presumptive evidence for coagulation factor deficiencies and inhibitors, though you may still want to send out your factor assays and lupus anticoagulant profiles. I hope this helps.