What Is the Connection Between Protein S and C?

Protein C (protein C, PC) is an important vitamin K physiological anticoagulant protein (its cofactor protein S). The main anticoagulant and antithrombotic functions of activated protein C (APC) include Inactivation of activated clotting factor V (FVa) and activated clotting factor a Activated clotting factor (Fa), restriction of binding of activated clotting factor Xa (FXa) to platelets, enhancement of fibrinolysis, increase of antithrombin and thrombin binding Anticoagulation. On the other hand, when the FV gene is mutated (FV Leiden mutation), it can cause activated protein C resistance (APCR) and cause thrombosis.

Protein C (protein C, PC) is an important vitamin K physiological anticoagulant protein (its cofactor protein S). The main anticoagulant and antithrombotic functions of activated protein C (APC) include Inactivation of activated clotting factor V (FVa) and activated clotting factor a Activated clotting factor (Fa), restriction of binding of activated clotting factor Xa (FXa) to platelets, enhancement of fibrinolysis, increase of antithrombin and thrombin binding Anticoagulation. On the other hand, when the FV gene is mutated (FV Leiden mutation), it can cause activated protein C resistance (APCR) and cause thrombosis.

PC tests include: protein C activity (PC: A) detection and protein C antigen detection.

(protein C antigen, PC: Ag) detection.

Name

Protein C

category

blood

Protein C reference interval

PC: A (plasma coagulation method): 70% to 140%.

PC: Ag (Immune Rocket Electrophoresis): 62% to 143%.

Clinical significance of protein C

(1) Hereditary PC deficiency: Type I individuals have reduced PC: Ag content and activity, while type II individuals have normal PC: Ag content and decreased activity.

(2) Acquired PC deficiency: DIC, liver disease (such as acute hepatitis, chronic active hepatitis, cirrhosis), malignant tumors, vitamin K deficiency, and acute respiratory distress syndrome, etc., PC activity and antigenicity are reduced.

(3) Decrease in protein C: In the initial period of oral anticoagulant treatment, PC first decreases rapidly, which can produce a transient hypercoagulable state.

(4) Increased PC antigen and activity: Compensatory increase in coronary heart disease, diabetes and nephrotic syndrome.

Protein C considerations

(1) Simultaneous determination of PC: A and PC: Ag: helpful for the classification of PC defects.

(2) Although PC: A can reflect PC function, it is affected by lupus anticoagulant, high concentration F (> 250%) and so on. Such as APCR, there may be a pseudo shortening of the plasma clotting time. At this time, the test plasma can be diluted with the PC matrix-free plasma at a ratio of 1: 2 and 1: 4 to eliminate this effect.

(3) PC activity and antigen detection results are often not parallel, so each laboratory must establish its own reference interval.