A blood donation is when a person voluntarily has blood drawn and used for transfusions and/or made into biopharmaceutical medications by a process called fractionation (separation of whole-blood components).

Donation may be of whole blood (WB), or of specific components directly (the latter called apheresis). Blood banks often participate in the collection process as well as the procedures that follow it.

Today in the developed world, most blood donors are unpaid volunteers who donate blood for a community supply. In poorer countries, established supplies are limited and donors usually give blood when family or friends need a transfusion (directed donation). Many donors donate as an act of charity, but in countries that allow paid donation some donors are paid, and in some cases there are incentives other than money such as paid time off from work. Donors can also have blood drawn for their own future use (autologous donation). Donating is relatively safe, but some donors have bruising where the needle is inserted or may feel faint.

Potential donors are evaluated for anything that might make their blood unsafe to use. The screening includes testing for diseases that can be transmitted by a blood transfusion, including HIV and viral hepatitis. The donor must also answer questions about medical history and take a short physical examination to make sure the donation is not hazardous to his or her health. How often a donor can donate varies from days to months based on what component they donate and the laws of the country where the donation takes place. For example, in the United States, donors must wait eight weeks (56 days) between whole blood donations but only seven days between plateletpheresis donations and twice per seven-day period in plasmapheresis.[1]

The amount of blood drawn and the methods vary. The collection can be done manually or with automated equipment that takes only specific components of the blood. Most of the components of blood used for transfusions have a short shelf life, and maintaining a constant supply is a persistent problem. This has led to some increased interest in autotransfusion, whereby a patient's blood is salvaged during surgery for continuous reinfusion—or alternatively, is "self-donated" prior to when it will be needed. (Generally, the notion of "donation" does not refer to giving to one's self, though in this context it has become somewhat acceptably idiomatic.)

Donors usually are > 18 y old, are in good health and afebrile, and weigh > 110 lb (50 kg).

Donors are usually limited to 1 unit every 8 wk and 6 donations per year.

Patients with a history of hepatitis, HBsAg positivity, insulin-dependent DM, IV drug abuse, heart disease, anemia, or homosexual activity are excluded from routine donation. Donor blood is tested for ABO, Rh, antibody screen, HBsAg, anti–hepatitis B core antigen, hepatitis C antibody, anti–HIV-1 and -2, and anti–HTLV-1 and -2.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++

The standard blood donation involves phlebotomy through a large-bore needle inserted into an arm vein. Approximately 450 mL are transferred into a sterile plastic bag containing citrate phosphate dextrose (CPD)-adenine. Citrate (C) prevents coagulation by chelating calcium ions. The phosphate (P) buffer maintains the pH at physiologic levels. Dextrose (D) provides a source of energy during blood storage. Adenine enhances the viability of the stored red cells.

When a tube of anticoagulated blood sediments in a gravitational field, the relatively dense red cells go to the bottom, and the less dense white cells and platelets form a "buffy coat" layer on the upper surface of the red cells, whereas cell-free plasma is least dense and collects at the top of the tube. In the blood bank, the bag of freshly collected donor blood is first centrifuged at relatively low speed, allowing separation into packed red cells and platelet-rich plasma (Fig. 25-1). The platelet-rich plasma is then spun at a higher speed, enabling separation into cell-free plasma and a platelet concentrate (Fig. 25-1).

The separation of a 450-mL (one pint) unit of donor blood into packed red cells (RBC), platelet concentrate (PLT), and plasma FFP, fresh frozen plasma.

Packed red cells are stored at 4°C for up to 42 days. In most medical centers, the white blood cells are removed by a filter, a maneuver that lowers the incidence of febrile reactions and human leukocyte antigen (HLA) alloimmunization and reduces the risk of infection with cytomegalovirus. Patients undergoing hematopoietic stem cell transplantation receive red cell units that have been irradiated in order to reduce the risk of graft-versus-host disease.

The fresh plasma is frozen and stored at –18°C or colder for up to 1 year. The platelet concentrate is stored at 20°C for a maximum of 5 days. Typically, to prepare a transfusable dose of platelets, concentrates from six donors are pooled. An alternative way to collect platelets in numbers sufficient for transfusion involves circulating venous blood from a donor through an apheresis machine, which continuously removes platelets and returns red cells and plasma to the donor. Platelet units are also irradiated prior to administration to transplant patients.

Blood donation involves phlebotomy through a large-bore needle inserted into an arm vein. Approximately 450 mL are transferred into a sterile plastic bag containing citrate phosphate dextrose (CPD)-adenine. Citrate (C) prevents coagulation by chelating calcium ions. The phosphate (P) buffer maintains the pH at physiologic levels. Dextrose (D) provides a source of energy during blood storage. Adenine enhances the viability of the stored red cells.

When a tube of anticoagulated blood sediments in a gravitational field, the relatively dense red cells go to the bottom, and the less dense white cells and platelets form a "buffy coat" layer on the upper surface of the red cells, whereas cell-free plasma is least dense and collects at the top of the tube. In the blood bank, the bag of freshly collected donor blood is first centrifuged at relatively low speed, allowing separation into packed red cells and platelet-rich plasma. The platelet-rich plasma is then spun at a higher speed, enabling separation into cell-free plasma and a platelet concentrate.

The separation of a 450-mL (one pint) unit of donor blood into packed red cells (RBC), platelet concentrate (PLT), and plasma FFP, fresh frozen plasma.

Packed red cells are stored at 4°C for up to 42 days. In most medical centers, the white blood cells are removed by a filter, a maneuver that lowers the incidence of febrile reactions and human leukocyte antigen (HLA) alloimmunization and reduces the risk of infection with cytomegalovirus. Patients undergoing hematopoietic stem cell transplantation receive red cell units that have been irradiated in order to reduce the risk of graft-versus-host disease.

The fresh plasma is frozen and stored at –18°C or colder for up to 1 year. The platelet concentrate is stored at 20°C for a maximum of 5 days. Typically, to prepare a transfusable dose of platelets, concentrates from six donors are pooled. An alternative way to collect platelets in numbers sufficient for transfusion involves circulating venous blood from a donor through an apheresis machine, which continuously removes platelets and returns red cells and plasma to the donor. Platelet units are also irradiated prior to administration to transplant patients.