Factor IX is activated to IXa by the action of activated factor XI - factor XIa.
It goes on to activate factor X to Xa in the presence of phospholipid, calcium and factor VIIIa.
Deficiency of factor IX can lead to haemophilia B.
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.