Urine-based point-of-care testing for factor-Xa-inhibitors in acute ischemic stroke patients: a feasibility study

Abstract

Introduction: Direct oral anticoagulants (DOACs) have become widely used in clinical practice for preventing thromboembolic events. Point-of-care testing methods, particularly those based on urine samples, offer a promising approach for rapid and accurate assessment of DOAC presence. This pilot study aims to evaluate the utility of a urine-based DOAC dipstick test as a point-of-care tool for identifying DOAB presence in acute ischemic stroke (AIS) or transient ischemic attack (TIA) patients.

Patients and methods: This prospective pilot study included patients with AIS/TIA eligible for DOAC-measurement. After exclusion of 3 patients, 23 patients with DOAC-intake (DOAC group; factor-Xa-inhibitors; n = 23) and 21 patients without DOAC-intake (control-group) remained for analyses. The urine-based DOAC dipstick test and parallel blood-based specific DOAC-level assessment were performed in all patients. Time-intervals of sampling urine/blood sampling and result of DOAC-test were recorded to analyze a potential time benefit based on dipstick evaluation.

Results: The urine-based DOAC dipstick test demonstrated high sensitivity (100%) and specificity (100%), correctly identifying all patients with anticoagulatory activity due to DOAC intake (i.e., anti-Xalevel ≥30 ng/mL). Moreover, the visual readout of the test provided semiquantitative information on drug-specific anti-Xa levels, showing a sensitivity of 83% and specificity of 93% to detect anti-Xa levels ≥120 ng/mL. The dipstick test exhibited a median time-benefit of 2:25 h compared to standard blood-based DOAC-level testing.

Discussion: The results of this pilot study underline the efficacy of urine-based point-of-care testing as a rapid and reliable method for assessing DOAC presence in patients with acute ischemic stroke.

Conclusion: The value of this tool for clinical decision-making in stroke management needs to be established in future trials.Clinical Trial Registration: Clinicaltrails.org identifier [NCT06037200].

Keywords: anticoagulation; direct oral anticoagulant; factor-Xa-inhibitor; ischemic stroke; point-of-care test.

Figure 1

Distribution of drug-specific anti-Xa levels according to dipstick result. The distribution of drug-specific anti-Xa levels is depicted for all included patients, categorized based on the visual dipstick result. Circles represent a positive result obtained from the DOAC dipstick, while squares indicate a negative result. To improve clarity, only a subset of control patients is depicted in this figure for illustrative purposes (control patients not illustrated in this figure had all anti-Xa levels of 0 mg/mL). Additionally, dotted lines demarcate the area corresponding to true positive, false positive, true negative, and false negative results. DOAC, direct oral anticoagulant.

Figure 2

Distribution of specific anti-Xa levels according to (A) DOAC dosing and (B) time since last intake of DOAC. The distribution of drug-specific anti-Xa levels is depicted based on the dosing of DOAC (A) and the time since the last DOAC intake (B). Circles represent a positive result by the DOAC dipstick, while squares indicate a negative result. Abbreviation: DOAC indicates direct oral anticoagulant.

Figure 3

Association of drug-specific anti-Xa-levels and visual dipstick results. The receiver operating characteristic (ROC) analysis was conducted to assess the relationship between drug-specific anti-Xa levels and the visual result of the DOAC dipstick (+/++ illustrated as blue line, ++ illustrated as green line). The area under the curve (AUC) with the corresponding 95% confidence interval is presented. The Youden-Index, sensitivity, and specificity were calculated for both identified anti-Xa thresholds.