Point of care tests and apixaban levels

Abstract

The novel oral anticoagulant (NOAC) apixaban is a direct Factor Xa inhibitor that does not require routine monitoring.1,2 However, emergency situations including ischaemic stroke and urgent surgery may require rapid assessment of serum apixaban levels to guide clinical decision making. In these emergencies, a level of <30 ng/mL permits thrombolysis and urgent surgery.1–3 As apixaban level using anti-Xa assay has a long turnaround time,1,2 we conducted this study to evaluate the use of the point-of-care (POC) tests CoaguChek XS and ROTEM in measuring apixaban levels. 234 coagulation tests were performed on samples from 50 patients. CoaguChek XS showed poor concordance to apixaban level, making it unfit as POC measurement for apixaban level. ROTEM CT showed moderate concordance to apixaban level. When analysed for detecting apixaban level >100 ng/mL, ROTEM CT of >92 seconds showed excellent diagnostic performance (84% sensitivity, 89% specificity), but this is currently not clinically relevant. Analysis on significant threshold of 30 ng/mL was not done because no patients had level <30 ng/mL. This pilot study showed ROTEM CT may be useful as a POC test for estimation of apixaban level. Further research is warranted to assess diagnostic performance of ROTEM CT at clinically significant apixaban concentrations (30 ng/mL).