A urine-based point-of-care test for Factor Xa inhibitors in acute stroke management

For stroke patients with history of possible Direct Acting Oral Anticoagulant use, clinicians must make treatment decisions without knowledge of whether the patient is therapeutically anticoagulated. A urine-based point-of-care test might help guide these emergency decisions.

We prospectively enrolled patients with suspected recent factor-Xa-inhibitor (Xai) use being evaluated for acute stroke therapy in an urban teaching hospital. We obtained the urine test and plasma anti-Xa level in parallel with usual clinical management; the treating clinician did not use test results for decision-making but recorded treatment they would have given had they known the urine test was accurate. The primary outcome was feasibility. Secondary outcomes were accuracy of the urine test at plasma anti-Xa level >30 ng/mL and consequent change in clinical management.

Twenty-one patients were enrolled over 1 year. The urine test was successfully carried out in all patients, median 59 minutes after Emergency Department arrival. Sensitivity and specificity for the urine test to detect threshold anti-Xa activity were 100 % and 87.5 %. Of 20 patients with ischemic stroke, none of whom were treated with thrombolytics, 6 had a negative test which would have resulted in treatment of 4 (66 %).

A urine point-of-care test for Xai activity is feasible, accurate, and would likely result in treatment of stroke patients currently excluded from thrombolysis.