Clotting
Also called coagulation. Clotting is an important part of the haemostasis, a biological process to avoid blood loss and early repair of damaged blood vessels. The clotting process normally takes 4-8 minutes and results in a clot consisting of a fibrin mesh filled with platelets and erythrocytes. Clotting may be activated by different mechanisms, usually called the internal or external systems. The most common trigger of clotting is contact between the blood and a surface other than endothelial cell layer of the vessels (e.g. in bleeding or with foreign materials in blood stream). The multitude of biological substances involved in creating a clot is called the clotting cascade. The clotting cascade is characterised by molecules that are triggered by certain stimuli. An activated molecule may trigger the next step in the cascade. The final step of the clotting cascade is the formation of fibrin from fibrinogen. Clotting should not be confused with erythrocyte aggregation.
GE Healthcare Glossary