Abstract 102: Feasibility and utility of a quantitative urine‐based point‐of‐care test for Factor Xa in acute stroke evaluation: a single‐center pilot study (QUICK‐Xa)
Authors: Marella P. , Czap A. L. , Samburksy J. A. , Cohn B. , Simons T. , Jacob A. P. , Grotta J. C. 
Published: January 2025

Introduction
Direct oral anticoagulant (DOAC) medications are absolute contraindication to intravenous thrombolytics in acute ischemic stroke, increasing the risk of neurologic deterioration in cases of intracranial hemorrhage if not managed with reversal agent. The current serum assay, which detects DOAC activity via serum anti‐factor Xa levels, has prolonged processing time that is not conducive to prompt administration of time‐sensitive therapies in the acute stroke setting. However, urine‐based point‐of‐care (POC) test for detecting therapeutic levels of DOACs is available.

Objectives
Study aims to determine feasibility of implementing a urine‐based point‐of‐care test as a part of acute stroke evaluation in the emergency department (ED); establish the correlation between POC test results and serum anti‐factor Xa levels; assess the hypothetical impact of POC testing on treatment rates; and investigate the incidence of any treatment‐related complications in patients who are hypothetically managed based on POC testing.

Methods
In this non‐interventional study, all suspected acute stroke patients presenting to our MSU or ED with history of possible DOAC use within the past 48 hours if they have 1) disabling deficit AND 2) seen within 6 hours of last known normal, OR c) within 12 hours of last known normal and 3 hours of wake up, will be screened and enrolled. The following information will be obtained: time metrics for acute stroke evaluation and treatment, time to urine and serum sample acquisition, time to urine and serum laboratory result posting, serum anti‐factor Xa level, urine POC test result. The following questions will be answered by the treating physician: 1) prior to test result: I would have given TNK or reversal agent OR I would not have given TNK or reversal agent and 2) assuming you know that the test is reliable: Would the result of the test have changed your decision to give or not give a thrombolytic or a reversal agent? If it wouldn't had changed your decision, would the result of the test have made your decision to give or not give a thrombolytic or a reversal agent easier?

Results
We plan to enroll 20‐60 patients, including at least 10 patients with negative test. The primary outcomes will be measured: 1a) percent of successful POC testing among patients in whom the test is attempted and 1b) door‐to‐needle time for thrombolytic or hemorrhage reversal agent administration. Secondary outcomes will include: 1) correlation of urine‐based POC DOAC level test result to serum anti‐factor Xa level (sensitivity, specificity); POC result and anti‐Xa level will be interpreted in relation to confirmed time elapsed from last DOAC dose, 2) impact of test on treatment rates; assuming the test is accurate, the additional number (percent) of patients with negative test who the clinical team would have treated with thrombolytic or reversal agent; the additional number (percent) with positive test who would not have been treated with thrombolytic or reversal agent and 3) adverse events associated with therapy in patients whom the clinical team treated with thrombolytics and who had negative test, or with reversal agents and who had positive test.