PB1064 - Exclusion of relevant concentrations of direct oral anticoagulants in blood by DOAC Dipstick – proposal of a diagnostic algorithm for improvement of clinical decision-making in emergencies

Tuesday, July 12, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

IC

Ivana Celap, PhD

Head of the Department
Department of Clinical Chemistry, Sestre milosrdnice University Hospital Center
zagreb, Grad Zagreb, Croatia

Co-Author(s)

Sandra Margetic, PhD

Assist. prof., Head of Department for Laboratory Hematology and Coagulation
Department of Clinical Chemistry, Sestre milosrdnice University Hospital Center
Zagreb, Grad Zagreb, Croatia
JP

Josipa Periša

Medical biochemist
University Hospital Center Sestre milosrdnice
Zagreb, Grad Zagreb, Croatia
MR

Marija Razum

clinical chemist
Department of Clinical Chemistry, Sestre milosrdnice University Hospital Center
Zagreb, Grad Zagreb, Croatia
S�

Sandra Šupraha-Goreta

Specialist in Laboratory Medicine
Faculty of Pharmacy and Biochemistry, University of Zagreb, Croatia, Department of Biochemistry and Molecular Biology, Zagreb, Croatia
Zagreb, Grad Zagreb, Croatia
A�

Anesa Čajević Glojnarić

Medical biochemist
University Hospital Center Sestre milosrdnice
Zagreb, Grad Zagreb, Croatia

Background: Rapid and accurate determination of direct oral anticoagulants (DOACs) is still a major medical need in urgent clinical situations.

Aims: The aim of this study was to identify the feasibility of algorithm for rapid exclusion of clinically significant concentration of DOACs (>30 ng/mL) by data from in patients from cardiology and neurology departments.

Methods: The study included 128 paired plasma and urine samples from patients treated for non-valvular atrial fibrillation of venous thromboembolism with an oral direct factor Xa inhibitor (DXI) (apixaban, n=31, rivaroxaban, n=53) and direct thrombin inhibitor (DTI) (dabigatran, n=44) at trough drug levels. Plasma DOACs concentrations were determined by quantitative chromogenic substrate assays (Innovance anti-FXa assay for rivaroxaban and apixaban and Innovance DTI assay for dabigatran) on BCSXP analyzer (Siemens Healthineers, Germany). Urine samples were evaluated by DOAC Dipstick test (DOASENSE GmbH, Heidelberg, Germany) to determine the presence or absence of DOACs. Parameters of diagnostic accuracy were determined by receiver operating curve (ROC) analysis. Comparison between DOAC Dipstick test results and plasma concentrations of DOACs were obtained using kappa statistics. The study was funded as a part of Croatian Science Foundation research project IP-2016-06-8208.

Results: ROC analysis revealed threshold values of plasma concentrations for DXI ≥14 ng/mL and ≥19 ng/mL for DTI for detection of DXI and DTI by DOAC Dipstick, respectively. At cut-off value ≥19 ng/mL for DTI there was no false negative or false positive results (kappa value=1.0). For DXI at cut-off ≥14 ng/mL one false positive result was obtained, κ=0.92 (95 % CI 0.74-1.00).

Conclusion(s): Application of an algorithm for exclusion of relevant plasma concentrations by DOAC Dipstick can be proposed by testing first DOACs in urine and if positive followed by quantitative DOAC assays if clinically required.