Stable blood coagulation factor involved in the intrinsic pathway. The activated form XIa activates factor IX to IXa. Deficiency of factor XI is often called hemophilia C.

Synonyms: Coagulation Factor XI, Factor XI, Blood Coagulation Factor XI, Factor 11, Factor XI, Coagulation, Plasma Thromboplastin Antecedent, Factor Eleven, 9013-55-2, Blood-coagulation factor XI, Thromboplastin Antecedent, Plasma, Antecedent, Plasma Thromboplastin