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Effects of Direct Oral Anticoagulants on Coagulation Testing

Written by Mark Hill on .

The Direct oral anticoagulants (DOACs) require no laboratory monitoring, however the BCSH guidelines acknowledge that there may be circumstances where measurement of the concentration of the active drug or its effect may facilitate clinical management decisions (Kitchen et.al 2014). Each DOAC will interfere with almost all clotting tests to a varying degree, depending on the DOAC, assay principles and reagents used.

In order to aid with interpretation of coagulation assays when a DOAC is present in the patients plasma see this guide to illustrate the impact of DOACs on assays used within University Hospitals NHS Trust.

 If further advice is required please speak to Haematology.

 Measurement of non-coumarin anticoagulants and their effects on tests of Haemostasis: Guidance from the British Committee for Standards in Haematology. Steve Kitchen, Elaine Gray, Ian Mackie, Trevor Baglin and Mike Makris, on behalf of the BCSH committee. British Journal of Haematology, 2014, 166, 830–841.

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Edoxaban Assay

Written by Mark Hill on .

Edoxaban is one of the direct oral anticoagulants, exerting an anticoagulant effect by inhibiting activated factor X.

Changes in the prothrombin time (PT), international normalized ratio (INR), and activated partial thromboplastin time (aPTT) may be observed in patients on therapeutic edoxaban doses. However, these changes tend to be small, unpredictable, and highly variable, so clinicians should not use these markers to monitor the anticoagulant effects or titrate the dose of edoxaban (Plitt A, Giugliano RP. Edoxaban: review of Pharmacology and key phase I to III clinical trials. J Cardiovasc Pharmacol Ther. 2014;19(5):409–416).

Urgent requests should be discussed with the laboratory prior to receiving the sample.

This test will be reviewed by UKAS for ISO 15189 accreditation at the next surveillance visit in October 2019

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Gaucher's Disease

Written by Mark Hill on .

For advice on the investigation and diagnosis of Gaucher's Disease including contact details for referral of positive patients click here

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Apixaban and Rivaroxaban Assays

Written by Mark Hill on .

Haematology are now offering assays to measure the new oral anticoagulant drugs Apixaban and Rivaroxaban. Both drugs are direct factor Xa inhibitors. Apixaban is recommended by the National Institute for Health and Clinical Excellence for the prevention of stroke and systemic embolism in people with non-valvular atrial fibrillation and at least one of the following risk factors: prior stroke or transient ischemic attack, age 75 years or older, diabetes mellitus, or symptomatic heart failure. Apixaban and other newer anticoagulants (dabigatran and rivaroxaban) appear equally effective as warfarin in preventing non-hemorrhagic stroke in people with atrial fibrillation and are associated with lower risk of intracranial bleeding. For further information please contact the laboratory on 0121 424 0908 (internal ext 40908) or for clinical advice please contact the On Call Haematologist via switchboard.

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