Antithrombin III Activity (Plasma)

What Is Antithrombin III?

Antithrombin III is a natural anticoagulant in your blood that works by binding to enzymes involved in the clotting process. It helps prevent clots from forming where they shouldn’t, which is crucial for keeping blood flowing smoothly through your veins and arteries. Low levels can increase your risk of clotting disorders.

Why Might This Test Be Ordered?

Your healthcare provider may order this test if you have a history of blood clots, certain blood disorders, or if you’re taking medications that affect clotting. It may also be checked before surgery, during pregnancy, or if you have symptoms like unexplained bruising or bleeding.

What Does a Result Mean?

Results are typically reported as a percentage or ratio relative to a standard. While exact reference ranges vary by lab, very low levels may suggest conditions like antithrombin deficiency, which can raise clotting risks. High levels might be seen in certain medical conditions or treatments.

How Is This Test Performed?

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate plasma, where the antithrombin III activity is measured using specialized lab techniques.