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Does Apixaban Affect Clot-based Assays?

From Linda StangAlberta Health Services: As apixaban (Eliquis) is sure to start wreaking havoc in some of our special coag assays (read: tests will be ordered while patients are on this drug, but they WON’T tell us…), I did a search for publications about apixaban interference, and found nothing. Does anyone have any experience with interference in lupus anticoagulant panels (DRVVT– or SCT-based) or any other tests such as clot-based protein C or S assays, activated protein C resistance clot based assays, etc.?

Rivaroxaban (Xarelto) seems to be fairly obvious in our lupus anticoagulant panel as the DRVVT 1:1 mix samples are usually 75 seconds or above. They stand out like a sore thumb compared to the other patients, but I am not sure if any samples containing apixaban have come in, and just ‘slid under the radar.’

Thanks for your question, Linda. I’ll take a chance and suggest that apixaban will have the same effects on our clot-based assays as rivaroxaban, considering that both are direct anti-Xa anticoagulants, but I’ll ask for comments from those who have actually encountered apixaban in practice. Geo.

Comments (1)
Anticoagulant Therapy
Linda Stang
Apr 4, 2013 10:16am

From Linda Stang, Alberta Health Services,
From Linda Stang, Alberta Health Services, My theory about apixaban vs rivaroxaban: if you happen to run a sample from a patient on rivaroxaban on an anti-Xa assay with a hybrid curve more often than not you will get a very high value (i. e. >2.0), whereas apixaban reads about where LMWH/UNFH would read. Also, if you take a patient sample that reads 0.75 U/mL on an anti-Xa result read off a hybrid curve, and then try to run that sample on the Aniara rivaroxaban assay, it is hardly a blip on the radar. The Aniara assay does a very large dilution of patient sample–1/50 or close to it. To put it another way, I think rivaroxaban needs a whole pile of little anti-Xa soldiers to do its job, while the apixaban army seems to need a whole lot less of its soldiers to do the job. In other words, I don’t think the assay interference from apixaban is going to be quite as obvious as the Rivaroxaban–but I have been wrong before 😉

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