[Bleeding disorders caused by hyperfibrinolysis]

A novel disease entity, "bleeding disorders caused by hyperfibrinolysis," was designated in Japan as an intractable disease (No. 347) in 2025. Because this disorder is extremely rare and primarily defined by inherited genetic abnormalities, most clinicians encounter it only infrequently in practice. However, the underlying pathophysiology, excess fibrinolysis, is not necessarily rare. Hyperfibrinolysis has increasingly been recognized as one of the important mechanisms of bleeding in acquired conditions, including the ultra-acute phase of severe trauma, fibrinolysis-predominant disseminated intravascular coagulation, acute promyelocytic leukemia, malignancies, and aortic aneurysms. Therefore, a deeper understanding of hyperfibrinolysis, regardless of its cause, directly contributes to appropriate diagnosis and management of the underlying condition. This review outlines the clinical significance of the newly established concept of bleeding disorders caused by hyperfibrinolysis and discusses the diagnostic framework for assessing fibrinolytic activity, with particular emphasis on the role and clinical utility of fibrinolytic function testing.