Background: Increasing use of direct oral anticoagulants has led to rising numbers of requests for drug level measurement in routine laboratories. Although the same test is used, the anti-Xa assay, individual calibrator and control sets are required for each direct FXa inhibitor (DFXaI).

Aims: Proof of concept study to test usability of a single calibrator set with assigned values for edoxaban, rivaroxaban and apixaban.

Methods: A calibrator set composed of normal pooled plasma spiked with different levels of edoxaban was assigned calibrated values for edoxaban, rivaroxaban and apixaban traceable to LC-MS/MS of each DFXaI. On the new Ceveron c100 automated analyzer, TECHNOCHROM® anti-Xa assay was calibrated using the universal calibrator set separately for each DFXaI. For all drugs a high and low range application using different plasma pre-dilutions can be employed. Plasma samples from patients receiving one of the respective drugs were assessed using the appropriate LC-MS/MS method and TECHNOCHROM® anti-Xa assay calibrated for the respective drug.

Results: DFXaI-specific calibration curves were established using standard Ceveron c100 applications. As expected, correlation of anti-Xa determined edoxaban to mass spectrometry values for ex-vivo samples was 0.98. For ex-vivo rivaroxaban samples, Passing and Bablok regression between anti-Xa and LC-MS/MS exhibited a slope of 0.95 and intercept of < 2 ng/mL (pearson r 0.95). Similarly, the regression for ex-vivo apixaban samples generated a slope of 1.1 and correlation of 0.94.

Conclusions: Here we demonstrate the feasibility of a universal calibrator set which can be used to calibrate respective applications for edoxaban, rivaroxaban and apixaban using a chromogenic anti-Xa assay on a routine coagulation analyser. In addition, a similar approach can be used for a universal anti-Xa control set. A universal calibrator and control set for all anti-Xa assays has potential to reduce the cost of DFXaI measurement and improve throughput without compromising quality and traceability.

« Back to ISTH 2020 Congress

ISTH Congress Abstracts - https://abstracts.isth.org/abstract/feasibility-of-a-universal-calibrator-for-direct-fxa-inhibitor-doacs/