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Platelets are either isolated from collected units of whole blood and pooled to make a therapeutic dose, or collected by platelet apheresis: blood is taken from the donor, passed through a device which removes the platelets, and the remainder is returned to the donor in a closed loop. The industry standard is for platelets to be tested for ...
High platelet counts can occur in patients with polycythemia vera (high red blood cell counts), and is an additional risk factor for complications. [ citation needed ] A very small number of people report symptoms of erythromelalgia , a burning sensation and redness of the extremities that resolves with cooling, or aspirin or both.
One common definition of thrombocytopenia requiring emergency treatment is a platelet count below 50,000/μL. [5] Thrombocytopenia can be contrasted with the conditions associated with an abnormally high level of platelets in the blood – thrombocythemia (when the cause is unknown), and thrombocytosis (when the cause is known). [6] [7]
Platelets collected by using apheresis at an American Red Cross donation center. Not all platelet transfusions use platelets collected by automated apheresis. The platelets can also be separated from donations of whole blood collected in a traditional blood donation, but there are several advantages to separating the platelets at the time of collection.
A blood cell (also called a hematopoietic cell, hemocyte, or hematocyte) is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
Platelets are regulators of hemostasis and thrombosis. Platelets become active in the blood following vascular injury. Vascular injury causes platelets to stick to the cellular matrix that is exposed under the endothelium, form a platelet plug, and then form a thrombus. Platelets are essential in the formation of an occlusive thrombus and are ...
Exposure of blood to the subendothelial space initiates two processes: changes in platelets, and the exposure of subendothelial platelet tissue factor to coagulation factor VII, which ultimately leads to cross-linked fibrin formation. Platelets immediately form a plug at the site of injury; this is called primary hemostasis.
Thrombosis (from Ancient Greek θρόμβωσις (thrómbōsis) 'clotting') is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thrombocytes) and fibrin to form a blood clot to prevent blood loss ...