CASE REPORT article
Front. Immunol.
Sec. Autoimmune and Autoinflammatory Disorders : Autoimmune Disorders
Case Report: Differential diagnosis and clinical management of isolated prolonged activated partial thromboplastin time
Lu Liu
Dongmei Guo
Qilu Hospital of Shandong University (Qingdao), Qingdao, China
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Abstract
An unexpected, isolated prolongation of activated partial thromboplastin time (APTT) frequently poses diagnostic challenges in coagulation laboratories. This article presents two patients exhibiting isolated prolonged APTT, one with significant bleeding manifestations and another without bleeding symptoms. The first patient was diagnosed with acquired hemophilia A (AHA), whereas antiphospholipid antibodies (aPLs) were suspected to be responsible for the isolated prolonged APTT in the second patient. Accurate identification of the underlying cause of isolated prolonged APTT is crucial for proper diagnosis and subsequent therapeutic management. Furthermore, we summarize potential causes of isolated prolonged APTT and propose a simplified diagnostic algorithm to distinguish between lupus anticoagulants (LA) (more common) and coagulation factor deficiencies (less common). This report aims to provide insights into the clinical management of similar cases in the future.
Summary
Keywords
Acquired hemophilia, Antiphospholipid antibodies, APTT, case report, lupusanticoagulant
Received
30 October 2025
Accepted
17 February 2026
Copyright
© 2026 Liu and Guo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Dongmei Guo
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