Hypercoagulable Workup on Apixaban

Testing Strategy

The American College of Radiology recommends performing hypercoagulable workup while the patient remains on apixaban without interruption, as apixaban does not interfere with most thrombophilia testing and stopping anticoagulation poses significant thrombotic risk 1
The American College of Radiology suggests that genetic testing for Factor V Leiden mutation and Prothrombin G20210A mutation can be performed while on apixaban, as anticoagulation status does not affect genetic testing 1
The American College of Radiology recommends checking antiphospholipid antibodies, including anti-cardiolipin antibody, lupus anticoagulant, and anti-beta-2-glycoprotein I, while on apixaban therapy, although lupus anticoagulant may be affected 1
The American College of Radiology suggests assessing platelet count to evaluate for heparin-induced thrombocytopenia or other thrombocytopenic conditions while on apixaban 1

For patients with recent acute thrombosis (within 3 months), the American College of Radiology strongly recommends performing only the tests that can be done on therapy 1
The American Heart Association suggests that for patients with high CHA₂DS₂-VASc scores (≥2) or recent venous thromboembolism, the risk of interrupting apixaban may outweigh the benefit of complete testing 2

Standard coagulation tests, such as PT and aPTT, are unreliable for assessing apixaban levels, as a normal PT/aPTT does not exclude therapeutic or supratherapeutic apixaban levels 3
A prolonged PT suggests clinically important apixaban levels, but normal values are not reassuring 3
If quantitation of apixaban is needed, the American College of Radiology recommends using anti-Factor Xa assay calibrated specifically for apixaban 3

The National Kidney Foundation notes that apixaban clearance is prolonged in renal dysfunction, with a half-life of up to 17 hours 2
Severe renal impairment (CrCl <15 mL/min) is a relative contraindication to apixaban, according to the National Kidney Foundation 4