Plateletpheresis (also called thrombapheresis or thrombocytapheresis) is the process of collecting platelets, the components of blood that are involved in hemostasis (blood clotting). It can be a life-saving procedure in preventing or treating serious complications from bleeding and hemorrhage in patients who have disorders manifesting as thrombocytopenia (low platelet count) or platelet dysfunction. This process may also be used therapeutically to treat disorders resulting in extraordinarily high platelet counts such as Essential Thrombocytosis.