Which coagulation factor is known as the Christmas factor?

The coagulation factor known as the Christmas factor is Factor IX. This designation comes from the fact that its deficiency leads to hemophilia B, which was first identified in a patient named Stephen Christmas. This condition is characterized by a deficiency in Factor IX, leading to difficulty with blood clotting and increased susceptibility to bleeding.

Factor IX plays a crucial role in the coagulation cascade, specifically in the intrinsic pathway, where it activates Factor X in the presence of Factor VIII. Understanding the specific factors involved in coagulation is vital for diagnosing and managing bleeding disorders, such as hemophilia. Identifying Factor IX as the Christmas factor helps healthcare professionals associate specific deficiencies with the corresponding bleeding disorders they may encounter in patients.