In hematology what is PT and PTT?

In hematology, PT and PTT are important tests that measure the blood's ability to clot. Here's an explanation of each:

1. Prothrombin Time (PT):

- PT measures the time it takes for a blood sample to clot after adding specific reagents.

- It assesses the functionality of the extrinsic and common coagulation pathways, which involve the formation of fibrin, the protein responsible for clot formation.

- PT is used to evaluate disorders related to these coagulation pathways, including deficiencies of clotting factors (such as factors II, V, VII, and X), as well as the effects of anticoagulant medications such as warfarin.

2. Partial Thromboplastin Time (PTT):

- PTT measures the time it takes for a blood sample to clot after adding certain substances that activate the intrinsic coagulation pathway.

- It assesses the functionality of the intrinsic and common coagulation pathways, including the activation of factors XII, XI, IX, and VIII, as well as the availability of phospholipids and calcium.

- PTT is used to evaluate disorders related to these coagulation pathways, including deficiencies of clotting factors (such as factors VIII, IX, XI, XII, and von Willebrand factor), as well as the effects of anticoagulant medications like heparin.

Both PT and PTT are crucial tests in the diagnosis and monitoring of bleeding and clotting disorders, such as hemophilia, von Willebrand disease, disseminated intravascular coagulation (DIC), liver disease, and the effectiveness of anticoagulant therapy.