Factor IV corresponds to which chemical used in coagulation?

Factor IV corresponds to which chemical used in coagulation?

• A. Proaccelerin/Labile Factor
• B. Tissue Thromboplastin
• C. Calcium
• D. Fibrinogen

Answer: (C)

Factor IV is calcium, the ionic calcium that acts as an essential cofactor in the coagulation cascade. Calcium ions enable coagulation factors to bind to phospholipid surfaces on platelets and cell membranes, allowing a sequence of proteolytic activations that convert prothrombin to thrombin and fibrinogen to fibrin. In the lab, removing calcium with citrate stops coagulation, and adding calcium back restarts it. Clinically, calcium salts (like calcium gluconate) are used to reverse citrate anticoagulation and support clotting when needed. The other items refer to different factors: a labile factor is factor V, tissue thromboplastin is tissue factor (factor III), and fibrinogen is factor I.

Factor IV is calcium, the ionic calcium that acts as an essential cofactor in the coagulation cascade. Calcium ions enable coagulation factors to bind to phospholipid surfaces on platelets and cell membranes, allowing a sequence of proteolytic activations that convert prothrombin to thrombin and fibrinogen to fibrin. In the lab, removing calcium with citrate stops coagulation, and adding calcium back restarts it. Clinically, calcium salts (like calcium gluconate) are used to reverse citrate anticoagulation and support clotting when needed. The other items refer to different factors: a labile factor is factor V, tissue thromboplastin is tissue factor (factor III), and fibrinogen is factor I.