What term describes the clumping together of particles or substances, particularly in blood?

The term that describes the clumping together of particles or substances, especially in the context of blood, is agglutination. This process occurs when antibodies bind to specific antigens on the surface of blood cells (such as red blood cells), causing them to stick together. This is a critical reaction in various immune responses, including blood typing, where agglutination can indicate the presence or absence of specific blood group antigens.

Coagulation refers to the process where blood changes from a liquid to a gel, forming a blood clot, which involves multiple factors including platelets and clotting proteins. Hemostasis is the overall process that prevents and stops bleeding, involving vascular constriction, platelet plug formation, and coagulation. Thrombosis is the formation of a blood clot inside a blood vessel, which can lead to several complications if it obstructs blood flow. Understanding these distinctions highlights why agglutination specifically refers to the clumping of cells or particles, particularly in immunological contexts.