Processing blood platelets. Bags of platelets from donor blood, next to a centrifuge that is used to concentrate the platelets from plasma, the liquid component of blood. Platelets (thrombocytes) are essential for blood clotting. They are suspended in the plasma, giving a yellow colour. The other cellular components of the blood have been removed for use elsewhere. Plasma is further processed for a variety of blood products. Platelets are used to treat platelet deficiencies and disorders like thrombocytopenia. Platelets can be stored at room temperature for up to five days.