“The only reason I’m alive today is the Red Cross provided the blood and platelets for the many transfusions that I needed.”
— Keone Penn
Platelets are small, disk-shaped cell fragments present in blood.
When bleeding from a damaged blood vessel occurs, platelets become activated and stick together to form a platelet plug to immediately stop the bleeding. The activated platelets in the plug stimulate a cascade of changes that activate clotting proteins in the blood. These clotting proteins ultimately cause a change in a blood protein called fibrinogen to form fibrin strands, which resemble tiny threads. The fibrin strands combine with the platelet plug to form a strong web-like mesh over the injured part of the blood vessel — a “scab” — to prevent bleeding while the injury heals.
Platelets are produced in our bone marrow. There is a hormone called Thrombopoietin [throm"bō-poi'i-tn], which is mainly produced by the liver, that stimulates platelet production.
Platelets circulate within your body for approximately 5 to 9 days. After this period, they are stored in the spleen. Decreased function (or absence) of the spleen may increase platelet counts, while hypersplenism, an over activity of the spleen, in diseases like leukemia, may lead to increased elimination resulting in low platelet counts.
Chemotherapy can affect the body’s ability to produce platelets, so cancer patients often require platelet transfusions. To prevent life-threatening bleeding, many patients with leukemia, aplastic anemia and those undergoing bone marrow transplants must regularly receive platelets donated by healthy volunteers.
Once donated, this living gift must be transfused to a patient within five days. To assure that platelets are always available, and that each patient will receive the platelets that are the best match, platelet donations are needed every day.
