Factor IX is a crucial protein in the blood that helps with the clotting process. It is part of a series of proteins that work together to stop bleeding when injuries occur. When a blood vessel is damaged, factor IX activates and plays a key role in forming a clot, which prevents excessive blood loss. People with a deficiency in factor IX may experience a condition known as hemophilia B. This genetic disorder can lead to prolonged bleeding and easy bruising. Treatment often involves infusions of factor IX to help manage and prevent bleeding episodes, allowing individuals to lead more normal lives.