Why do the INR and PTT measure different pathways …
INR: extrinsic, PTT: intrinsic – is it really that simple …
7/29/2014 · The INR/PT tests only the extrinsic pathway (and the final common pathway). You’re right about the PTT, though: it tests only the intrinsic pathway (and final common pathway). This is because although the intrinsic and extrinsic pathways are dependent on each other (and must both work well) in the body, they are not dependent on each other in the lab.
PT is a functional measure of the extrinsic pathway and common pathway, and the reference range is 8.8–11.6 s. Therefore, PT is a useful test to detect inherited or acquired defects in coagulation related to extrinsic pathway. However, often PT is reported as international normalized ratio (INR).
2/4/2014 · The extrinsic pathway gets turned off after that (and the intrinsic pathway takes over), but at that point it doesn’t matter! Fibrin has been formed, and the test is done. So yes: people with a normal coagulation system have a normal PT despite the fact that the extrinsic pathway only plays an.
2/10/2014 · To understand why the PT measures just the extrinsic pathway and the PTT measures just the intrinsic pathway, you need to know what activates these pathways in the body. The extrinsic pathway is activated by tissue factor. The intrinsic pathway can be activated by a bunch of things, the most important of which is thrombin. Why the INR measures the extrinsic pathway To get blood in a test.
The extrinsic pathway of blood coagulation. Upon the introduction of cells, particularly crushed or injured tissue, blood coagulation is activated and a fibrin clot is rapidly formed. The protein on the surface of cells that is responsible for the initiation of blood clotting is known as tissue factor, or tissue thromboplastin.
7/5/2017 · Extrinsic pathway is a type of blood coagulation pathway that is activated when the traumatized vascular wall or the extra-vascular tissues come into contact with the blood. Efficiency: Intrinsic Pathway is slow. Extrinsic Pathway is explosive. Duration: Intrinsic pathway takes about 1 to 6 minutes to form a clot.
