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Updated: Nov 21, 2025
13:08
Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
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[Acquired factor V inhibitor associated with apixaban]
Yuichi Tochino1,2, Toshiki Mushino1,2, Yoshikazu Hori1,2,3
1Department of Hematology/Oncology, Wakayama Medical University.
[Rinsho Ketsueki] the Japanese Journal of Clinical Hematology
|January 14, 2021
Summary
This case report details a rare acquired factor V inhibitor in a patient treated with apixaban, a direct factor Xa inhibitor. The condition resolved with prednisolone, highlighting a new drug association.
Area of Science:
- Hematology
- Coagulation Disorders
Background:
- Acquired factor V inhibitor is a rare coagulation disorder.
- Patients with cardiovascular conditions often require anticoagulation therapy.
Observation:
- A 76-year-old man on aspirin and clopidogrel developed cerebral infarction post-PCI.
- Apixaban was added, followed by recurrent intramuscular and subcutaneous hemorrhages.
- Discontinuation of anticoagulants did not resolve the bleeding, suggesting an inhibitor.
Findings:
- The patient was diagnosed with acquired factor V inhibitor, with factor V activity <1% and inhibitor level 8.0 BU/ml.
- Treatment with prednisolone normalized coagulation tests (PT and APTT).
Implications:
- This is the first reported case of acquired factor V inhibitor associated with apixaban, a direct factor Xa inhibitor.
- Highlights the importance of considering acquired factor V inhibitor in patients presenting with unexplained bleeding while on anticoagulation.
- Suggests a potential need for revised anticoagulant strategies in susceptible individuals.
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