Prothrombin Time (PT) Blood Test

The Prothrombin time (PT) test is most often used to check how well anti-coagulant or “blood-thinning” drugs are working. This is particularly important in people who have had a heart attack or other problems with their veins. The effectiveness of natural and drug treatments can be determined by how much it prolongs the prothrombin-to-thrombin conversion time.

The PTT test is used when someone has unexplained bleeding or clotting. Along with the PT test (which evaluates the extrinsic and common pathways of the coagulation cascade), the PTT is often used as a starting place when investigating the cause of bleeding. It is often used with recurrent miscarriages that often are associated with anticardiolipin and phospholipid antibodies. The PTT and PT tests are also sometimes used as pre-surgical screens for bleeding tendencies, although numerous studies have shown that they are not useful for this purpose. The PTT is also used to monitor heparin anticoagulant therapy as well as other therapeutic anticoagulants such as hirudin or argatroban.

Those with antiphospholipid syndrom (APS) and other clotting disorders are recommended to run this test to monitor their clotting abilities.

What’s Being Tested:

• Prothrombin Time (PT)
• Partial Thromboplastin Time (PTT)

Fasting: No

Specimen: Blood (Draw Location | How It Works | FAQs)