In October 2018, a joint project between the Royal College of Pathologists Quality Assurance programs (RCPAQAP), the Institute of Clinical Pathology and Medical Research (ICPMR) (NSW Health Pathology, Westmead) and Western Australia Centre for Thrombosis and Haemostasis (WACTH) at Murdoch University WA, involved an additional sample dispatch to all participants enrolled in the Special Haemostasis Lupus Anticoagulant program. Four samples were provided with different clinical scenarios and laboratories were asked to perform their normal LA testing. In order to assure blind testing of samples, the project required non-disclosure of the actual sample types. We can now reveal that this was an exercise to evaluate the effect of rivaroxaban, a direct oral anticoagulant (DOAC), on LA testing, and whether the interference caused by rivaroxaban could be neutralised by either a commercially available product (DOAC Stop) or the clinical antidote (Andexanet alfa).
This is the first ever such evaluation performed as a cross-laboratory (n=82) exercise, and the results of the study have now been published in Thrombosis Research.
As an overview of the results:
- DOACs, especially rivaroxaban, interfere with LA testing and can generate false positive LA.
- ‘DOAC Stop’ (commercial product) can neutralise DOAC interference, and nullify rivaroxaban induced false positive LA.
- Andexanet Alpha (clinical rivaroxaban antidote) only partially neutralises the rivaroxaban induced false positive in vitro.
We thank participants of the RCPAQAP for their participation in the exercise. We are able to share with you a web-link that enables free access to the full article for the next 50 days (until July 20, 2019). If you wish to read the article and discover more, please click here. The article is free to read or download. No sign-up, registration or fees are required.
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