Guidance-Based Appropriateness of Hemostasis Testing in the Acute Setting.

In this review, we aim to highlight the extent of inappropriate hemostasis testing and provide practical guidance on how to prevent it. We will focus on the acute setting, including but not limited to the emergency department and intensive care unit. To this end, we will first discuss the significance of inappropriateness, in the general context of laboratory medicine. This includes acknowledging the importance of the phenomenon and attempting to define it. Next, we describe the harmful consequences of inappropriate testing. Finally, we focus on the inappropriate use of hemostasis testing in the acute setting. The second section describes how interventions-in particular, the implementation of guidance for testing-can efficiently reduce inappropriateness. In the third section, we summarize the available recommendations for rational use of hemostasis testing (platelet count, activated partial thromboplastin time, prothrombin time/international normalized ratio, fibrinogen, thrombin time, D-dimer, anti-Xa assay, antithrombin, ADAMTS13 activity, antiheparin-PF4 antibodies, viscoelastometric tests, coagulation factors, and platelet function testing), as supported by guidelines, recommendations, and/or expert opinions. Overall, this review is intended to be a toolkit in the effort to promote the appropriate use of hemostasis testing. Hopefully, the new In Vitro Diagnostic Medical Device Regulation (EU) 2017/746 (IVDR) should help in improving the availability of evidence regarding clinical performance of hemostasis assays.