Functional Antithrombin III (AT III)

Also known as: Functional Antithrombin III; AT III
Formal name: Antithrombin (Activity and Antigen)
Related tests: PTT; Coagulation factors; D-dimer; Fibrinogen; Homocysteine; Lupus Anticoagulant; Proteins C & S; PT; PT 20210; Factor V Leiden

Why should I do it?
To help investigate the cause of recurrent inappropriate blood clotting; to help diagnose an antithrombin deficiency

When should I do it?
A couple of months after a thrombotic episode or if you are not responding as your doctor expected to heparin anticoagulation therapy

What Kind of Sample is Needed?
A blood sample drawn from a vein in your arm

Test Preparation Needed?
None