SCIENCE@home

Thrombophilia testing in patients taking direct oral anticoagulants. Handle with care

G. Lippi,C. Mattiuzzi,E. Favaloro

Published 2014 in Diagnosis

ABSTRACT

We read with interest the recent letter of Chandrashekar, who further emphasized that results of thrombophilia testing may be confounded by the incident administration of oral vitamin K antagonists (VKAs), and that this potential interference may be detected by elevated prothrombin time (PT) and activated partial thromboplastin time (APTT) [1]. This was also seen in work previously published by one of us [2], where an alarming 80% of so-called low protein C, protein S and/or antithrombin levels in diagnostic test practice derived from cases likely to be on conventional anticoagulant therapy (VKAs or heparin) at the time of testing. Thus, there is ample evidence that blood sampling for thrombophilia screening should be avoided in patients taking conventional anticoagulants such as VKAs. However, differing and more complex conclusions may need to be applied to the direct oral anticoagulants (DOACs), either the activated factor II (FIIa) inhibitor dabigatran or the activated factor X (FXa) inhibitors rivaroxaban, apixaban and edoxaban. This is an important consideration, given the ever-increasing number of patients taking these agents. With the only exception of edoxaban, the influence of these novel and largely clinically effective therapeutic agents on conventional hemostasis assays has been thoughtfully investigated over the past few years [3–7], and the main findings are summarized in Table 1. In brief, none of the recommended tests for assessment of protein C (chromogenic) or protein S (free) has proven to be significantly biased by the presence of DOACs, even at the peek levels of the drugs [8]. However, the same will not apply to clot-based assays for protein C and protein S. As regards antithrombin, this parameter can be assessed by means of FX-based chromogenic assays in patients taking FIIa inhibitors, and by means of FII-based chromogenic assays in patients taking FXa inhibitors, respectively. However, utilising FX-based chromogenic assays in patients taking FXa inhibitors, and FII-based chromogenic assays in patients taking FIIa inhibitors will be problematic and lead to false identification of deficiencies. The activated protein C resistance (APCr) assay exhibits

PUBLICATION RECORD

CITATION MAP

EXTRACTION MAP

CLAIMS

  • No claims are published for this paper.

CONCEPTS

  • No concepts are published for this paper.

REFERENCES

Showing 1-10 of 10 references · Page 1 of 1

CITED BY

Showing 1-15 of 15 citing papers · Page 1 of 1