Antihemophilic (Christmas) factor B (F IX)

Formal name:VIII also known as Antihemophilic factor A, IX also known as Antihemophilic factor B (Christmas factor)
Related tests:Prothrombin Time (PT); Partial Thromboplastin Time (PTT); Fibrinogen; von Willebrand Factor

Why should I do it?
To determine whether levels of one or more of your coagulation factors are increased, normal, or decreased

When should I do it?
When you have unexplained or prolonged bleeding, an abnormal Prothrombin Time (PT) or Partial Thromboplastin Time (PTT) test, or have a relative with a hereditary coagulation factor deficiency; you may be tested when your doctor wants to monitor the severity of a factor deficiency and/or the effectiveness of treatment.

What Kind of Sample is Needed?
A blood sample obtained by inserting a needle into a vein in the arm

Test Preparation Needed?
None