Whole blood donation represents the standard method, where a pint of blood containing red cells, plasma, and platelets is collected simultaneously. Platelet donation, known as apheresis, is a more specialized process that selectively harvests only the platelets. This article clarifies the differences in how these products are collected, stored, and used by patients.
The Difference in Donation Processes
The physical act of donating whole blood is a rapid, straightforward procedure involving a single venipuncture. The actual blood draw typically takes about 8 to 10 minutes, with the entire appointment, including registration and post-donation rest, often completed within one hour. After collection, the donated whole blood is separated into its various components, which are then stored individually for patient use.
Platelet donation utilizes a process called apheresis, which requires specialized machinery to separate the blood components during the donation itself. Blood is drawn from the donor, passed through the apheresis machine to extract the platelets, and then the remaining components, such as red blood cells and plasma, are returned to the donor’s body. This cyclical process usually requires the use of two needles, one for drawing blood and one for returning the components.
The time commitment for apheresis is substantially longer than for whole blood. A platelet donation typically takes between 90 minutes and two hours to complete, followed by a short recovery period. Many donors find the process comfortable, as the return of red blood cells means less overall fluid loss compared to a whole blood donation.
Defining the Need: How Platelets and Whole Blood are Used
Donated whole blood is primarily processed into its individual components: red blood cells, plasma, and platelets. Red blood cells are perhaps the best-known component, used to restore oxygen-carrying capacity in patients suffering from acute blood loss due to trauma, surgery, or severe anemia. These red cells can be stored under refrigeration for up to 42 days, providing a relatively stable inventory for hospitals.
Platelets, small cell fragments that promote clotting, are frequently needed by patients whose bodies cannot produce enough of their own or whose platelets are dysfunctional. This includes individuals undergoing intensive treatments like chemotherapy for cancer, organ transplant recipients, and patients with severe bleeding disorders. A single apheresis donation can yield a therapeutic dose equivalent to the platelets from several whole blood donations, reducing exposure to multiple donors.
Platelets have an exceptionally short shelf life—only five to seven days—and must be stored at room temperature with continuous agitation. This limited storage time means blood centers must constantly replenish their supply. Conversely, plasma can be frozen and stored for up to a year, offering a much longer window of usability.
Donor Requirements and Frequency Allowed
All blood donors must meet general health criteria, including being in good health and typically weighing at least 110 pounds. However, the frequency with which a person can donate differs significantly between whole blood and platelets due to the body’s recovery time for each component.
Whole blood donation removes a significant quantity of red blood cells, which the body takes longer to replenish, particularly the iron stores. Consequently, the standard interval between whole blood donations is 56 days, or approximately eight weeks. This waiting period ensures the donor’s iron and hemoglobin levels have adequately recovered before the next donation.
Platelet donation is allowed much more frequently because the red cells and most of the plasma are returned to the donor. A platelet donor can safely donate as often as every seven days, up to 24 times within a 12-month period. This higher frequency is possible because the body replenishes platelets much faster than it replaces red blood cells.