DOACs plasma levels remained stable after 24h storage under various conditions, with recoveries between 93% to 102% and minor biases unlikely to affect clinical interpretation.
Does 24-hour storage under different conditions affect the reliability of DOAC plasma level measurements in patients taking DOACs?
DOAC plasma levels remain stable and accurate after 24 hours of storage under various conditions, allowing for deferred measurement in clinical practice.
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ABSTRACT Background Direct oral anticoagulants (DOACs) have simplified anticoagulant therapy, but plasma level testing (i.e., anti‐Xa and anti‐IIa activities) remains important in specific clinical situations (e.g., emergency surgery, bleeding, renal impairment, or suspected non‐adherence). However, the impact of sample storage on assay reliability is not well defined. This study evaluated the stability and potential systematic errors in DOACs (apixaban, rivaroxaban, edoxaban, dabigatran) plasma levels after 24 h storage under different conditions. Methods We enrolled 182 patients on one of the four DOACs. Blood samples were collected in duplicate citrated tubes. The first tube was processed within 4 h to obtain baseline values, with plasma successively stored at room temperature, 4°C, and −20°C for 24 h. The second tube was stored as whole blood at room temperature before measuring DOACs concentrations. DOACs were measured using dedicated clotting or chromogenic assays. Stability was assessed using non‐parametric statistics, Passing‐Bablok regression, and Bland–Altman analysis, with Acceptable Change Limits based on assay variability. Results All DOACs showed good stability across conditions, with median recoveries ranging from 93% to 102%. No significant proportional errors were observed. Minor constant biases were observed for apixaban (at 4°C and −20°C), and more consistently for rivaroxaban and edoxaban. Dabigatran showed no significant bias. Variability was generally low (< 7%), and most measurements near clinical thresholds remained accurate. Conclusion DOACs plasma levels remain stable after 24 h storage under various conditions. While minor biases exist, particularly for rivaroxaban and edoxaban, they are unlikely to affect clinical interpretation in most cases. Whenever needed, DOACs measurement can be deferred after blood drawing without jeopardizing results interpretation.
Sorrentino et al. (Mon,) reported a other. DOACs plasma levels remained stable after 24h storage under various conditions, with recoveries between 93% to 102% and minor biases unlikely to affect clinical interpretation.