PB1119 - Evaluation of Assay Performance Measuring Plasma Concentrations of Apixaban, Edoxaban, Rivaroxaban Using a Standard Heparin Reagent on a Fully Automated Coagulation Analyser

Background: The direct oral anticoagulants apixaban, rivaroxaban and edoxaban are used more and more frequent in patients. Therefore, the determination of these DOAC levels in clinical routine is necessary and recommended in cases of urgent invasive procedures or bleeding events.

Aims: The aim of this study was to evaluate the performance of the measurement of apixaban, edoxaban and rivaroxaban using a standard heparin assay by means of adapting a testing protocol and using DOAC specific lyophilized calibrators and controls on the Roche cobas® t-coagulation analyzer. In addition, a method comparison of patient’s sample results with those measured with mass spectrometry was performed.

Methods: A standard heparin reagent setting was adapted for the determination of apixaban, rivaroxaban and edoxaban levels in patient plasma on a cobas t coagulation analyzer. Lyophilized DOAC specific calibrators with assigned values determined by mass spectrometry (LC-MS/MS) were used for assay calibration. Controls with assigned values as well as in vitro spiked plasma were used to determine assay performance parameters. Patient sample levels were compared to those obtained with HPLC/MS-MS reference method to evaluate assay correlation.

Results: For each of the DOACs apixaban, rivaroxaban and edoxaban analyzer-settings for the low range 0-150ng/mL and high range 50-500ng/mL were established for the evaluation. Linearity was shown with different lots of all three DOACs between 0 and 500ng/mL with the respective applications. LoQ was determined to be below 10ng/mL. For all samples covering the whole assay range, both repeatability and reproducibility were well below 10%CV. Method comparison of patient plasma samples for all three DOACs exhibited very good correlation to values determined by mass spectrometry with a Passing-Bablok regression of approximately 1.0 and a Pearson correlation of >0.9.

Conclusion(s): Here we have demonstrated a suitable system to measure plasma concentrations of apixaban, rivaroxaban and edoxaban using a standard heparin assay on cobas t coagulation analyzers.