Description
Prothrombin Time with INR blood test determines how quickly your blood clots. It measures how many seconds it takes to clot after substances (reagents) are added. This is a screening test for abnormalities of coagulation factors that are involved in the extrinsic pathway. Also used to monitor effects of Warfarin therapy and to study patients with hereditary and acquired clotting disorders. It’s often used to help detect a bleeding disorder or clotting disorder and can help a doctor determine the cause, if present. It may sometimes be used before surgery or other invasive procedures to determine if excessive bleeding or clotting problems may be likely to occur.
In order for blood to clot, a certain sequence of activities called the coagulation cascade occurs. The clotting cascade depends on proteins called clotting factors, which activate each other in a step-by-step process. For blood to clot properly, there needs to be enough of each coagulation factor and they need to function properly. A problem with any of them can affect your body’s ability to form a clot.
The clotting cascade happens through two pathways— the intrinsic pathway and the extrinsic pathway. Each pathway involves certain factors, and while each pathway is separate, they interact with each other and finish in what’s called the common pathway.
