Basic-Principles-of-Hemostasis-SECONDARY -LATEST-3-22-23

Protein C

A major inhibitor of blood coagulation produced by the liver, inactivates Factors VIII:C and Va in the presence of Protein S.

Protein S

A vitamin K dependent protein that enhances the binding of Protein C to phospholipid surfaces; only free PS acts as a cofactor.

Thrombomodulin

A protein produced by endothelial cells that inactivates the clotting cascade by inducing thrombin to activate Protein C.

Antithrombin III

A Serpin that is a major inhibitor of thrombin and Factor Xa, with activity enhanced by heparin.

Heparin cofactor II

A Serpin that inhibits thrombin rapidly in the presence of dermatan sulfate or heparin.

Alpha 2 Macroglobulin

A Serpin that forms complexes with thrombin and kallikrein, thus inhibiting their activities.

Extrinsic Pathway Inhibitor (TFPI)

An inhibitor from endothelial cells that regulates the TF pathway by inhibiting Factor Xa.

C1 inhibitor

A protein that inactivates Factor XIIa, kallikrein, Factor XIa, and plasmin.

Chromogenic anti-Xa heparin assay

A test used to monitor unfractionated heparin (UFH) therapy.

International Normalized Ratio (INR)

A standardized method to report prothrombin time (PT) for patients on oral anticoagulant therapy.

Prothrombin Time (PT)

A test that measures the extrinsic and common pathway of coagulation, used to monitor anticoagulant therapy.

Activated Partial Thromboplastin Time (APTT)

A test to measure deficiencies in factors of the intrinsic and common pathways of coagulation.

DIC (Disseminated Intravascular Coagulation)

A condition that can prolong PT and APTT due to consumption of clotting factors.

Acquired hemophilia

The presence of antibodies against coagulation factors, often associated with autoimmune disorders.

Lupus anticoagulants

Not clinical manifesting antibodies that can neutralize the phospholipid reagent in coagulation tests, leading to prolonged APTT.