Question

3 What is the difference between the PT, aPTT, ACT, and INR lab tests, and why are they important to pharmacotherapy?

Answer 1

A PT test (prothrombin test) is used to detect and diagnose a bleeding disorder or excessive clotting disorder. The prothrombin talwar measures the speed of clotting by means of extrinsic pathway.

The aPTT test (activated partial thromboplastin time) is used to measure the intrinsic and common pathways of coagulation. It is used to measure the absence of any clotting factors or any change in the activity of clotting factors.

The ACT test (activated clotting time) can be used to monitor anticoagulation effects, such as high-dose heparin before, during, and shortly after procedures that require intense anticoagulant administration, auch as ECMO, continocon dialysis and cardiac bypass. It measures the time (seconds) needed for whole blood to clot upon exposure to an activator of an intrinsic pathway by the addition of factor XII activators.

The INR lab test (International normalized ratio) is calculated from a prothrombin test results to measure how well the anticoagulants are working to prevent blood clotting.