CPT (Certified Phlebotomy Technician) Practice Exam

The element of the blood that is primarily responsible for achieving hemostasis is platelets. Hemostasis is the process that prevents and stops bleeding or hemorrhage. When a blood vessel is injured, platelets are activated and they adhere to the site of injury, aggregating to form a temporary 'platelet plug'. They also release chemical signals that promote further aggregation and attract other platelets to the site, contributing to the formation of a stable clot.

Red blood cells play a crucial role in transporting oxygen and carbon dioxide but are not directly involved in the clotting process. White blood cells are essential for the immune response and help fight infections, but they do not have a role in hemostasis. Plasma, while it contains the clotting factors essential for coagulation, serves more as the medium through which these factors operate, rather than being responsible for initiating the hemostatic process itself. Thus, platelets are the key components in achieving hemostasis.