Why get tested?
As part of an investigation of a bleeding or thrombotic episode; to monitor unfractionated (standard) heparin anticoagulant therapy

When to get tested?
When you have unexplained bleeding or blood clotting; when you are on unfractionated (standard) heparin anticoagulant therapy; sometimes as part of a pre-surgical screen

Sample required?
A blood sample drawn by needle from a vein in the arm