From Leslie Chaparro: We recently had a patient who had a mixing study ordered but who had recently taken tranexamic acid [TXA]. We exclude patients that have been on anticoagulants but have never really considered drugs that encourage clotting. How would this affect the patient’s mixing study? How do we keep up with all the new drugs and protocols and how do they affect coagulation results?
Hello, Leslie Chaparro, and thank you for your question. I’m attaching an open-access article; Gosselin RC, Marlar RA. Preanalytical variables in coagulation testing: setting the stage for accurate results. Semin Thromb Hemost 2019;45:433–48. The article provides some information about TXA. I will speculate, from the “data-free zone,” that TXA, which is an antifibrinolytic, has little effect on PT and PTT-based clot-based assays and that its half-life of two hours implies that we can proceed with testing after a four-hour wait.
The Gosselin/Marlar article provides fresh information about assay and specimen management in all of the current antithrombotic and anti-hemorrhagic therapeutics, but watch this space, as we will solicit opinions from several of our participants.