Acquired hemophilia masked by warfarin therapy

Rami Kantor*, Haim Mayan, Lena Puritz, David Varon, Zvi Farfel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


People without hemophilia but with autoantibodies specifically directed against the procoagulant activity of factor VIII are known to have acquired hemophilia. The bleeding diathesis in these patients is often severe and life-threatening. The definite laboratory diagnosis of this disorder includes demonstration of low factor VIII levels in plasma with a high titer of factor VIII inhibitors, but the initial suspicion for its presence should rise in view of a prolonged partial thromboblastin time (PTT) and a normal prothrombin time associated with an acquired bleeding disorder. Oral anticoagulant treatment is known to prolong PTT as well, and the merger of these 2 situations may cause delayed diagnosis of acquired hemophilia with devastating consequences. We describe here the first reported case of acquired hemophilia diagnosed in a patient treated with warfarin. In such patients prolonged PTT may be ascribed to warfarin therapy rather than to acquired hemophilia, thus causing a dangerous delay in diagnosis.

Original languageEnglish
Pages (from-to)197-201
Number of pages5
JournalAmerican Journal of the Medical Sciences
Issue number3
StatePublished - Mar 2000
Externally publishedYes


  • Acquired hemophilia
  • Factor VIII
  • Partial thromboblastin time (PTT)
  • Warfarin


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