Electroimmunoassay of factor IX in patients with liver damage and vitamin K unresponsive coagulation disorder.

Factor IX antigen and activity were assayed in a group of patients with liver disease and in a group of patients in coumarin therapy. In patients with liver disease there was a similar decrease in activity and antigen. On the other hand factor IX activity is decreased in coumarin treatment with factor IX antigen remaining normal. Factor IX electrophoretic mobility in liver disease is normal.