Blood donation is a vital part of worldwide healthcare. It relates to blood transfusion as a life-sustaining and life-saving procedure as well as a form of therapeutic phlebotomy as a primary medical intervention. Over one hundred million units of blood are donated each year throughout the world. This article will concisely discuss a short history of blood donation origin and purpose, blood testing, donor eligibility and selection, adverse effects of donation, blood donation as a primary medical intervention, and a brief discussion of pathogen reduction and inactivation for donated blood.
Blood donation is most often performed by inserting a large bore needle (16G or 18G) into a peripheral vein, usually within the antecubital fossa. Veins on the dorsum of the hand or other prominent veins may be used in some individuals who do not have an otherwise easily accessible antecubital vein.
Blood donation for transfusion is a vital step in the management of many clinical problems, with the two primary indications being anemia and acute blood loss. Blood donation itself is also used to primarily treat a small subset of medical conditions. At the beginning of the 20th century, Karl Landsteiner identified ABO blood groups, at which time blood typing of individuals was only beginning to be adopted as a universally standard practice. Due to the inability to prevent blood from clotting once removed from the donor and thus store and transfer blood to be delivered when needed later, transfusions were only carried out on a limited basis. Blood was transfused directly from donor to recipient without intervening storage or transport. This method worked for small numbers of patients and only on a small scale, as donors and recipients needed to be connected both in time and space. There was a time when lists of donors were maintained of persons locally available to be called in to donate to patients at any time as needed. Necessity drove the development of more flexible donation and storage practices when World War I began. "On-demand" blood donation was not feasible for such a large scale effort. Soldiers were dying of otherwise non-fatal wounds due mainly to the inability to perform a timely blood transfusion.
Concerted efforts to develop a means of storing and transferring blood to meet the war-time demands led to several discoveries. One, clotting was inhibited by adding citrate to the donated blood. Second, glucose was added to the solution to allow the red blood cells to remain viable for several weeks when stored in refrigerated conditions., The first time blood was "banked" as is common practice currently, was when Captain Oswald Hope Robertson of the US Army Medical Corps collected Group O blood, combined it with glucose, and stored it before the Battle of Cambrai in November 1917. This was a pivotal shift from the prior practices of "direct" blood donation to "indirect" blood donation, importantly separating donors from their recipients geographically and temporally. This development made blood donation and transfusion a much more practical and useful medical intervention.
Allogeneic and autologous blood transfusion have many indications. More than 108 million units of red blood cells are transfused annually worldwide, and as not all donated units are actually used, the number of donated units is higher still. Blood is donated for later transfusion either back to the donor or to another person, termed respectively "autologous" and "allogeneic" transfusion. The main indications for blood donation for transfusion include anemia and acute blood loss. Blood can also be donated for primary therapeutic purposes for the donor. This is called "therapeutic phlebotomy," or as it was known historically, "blood-letting." Unfortunately, this practice was used incorrectly for thousands of years as a supposed cure for all sorts of ailments. Currently, the main indications for blood donation as a primary therapeutic medical intervention include treatment of hereditary hemochromatosis or other hemoglobin synthesis or myeloproliferative disorders such as polycythemia and porphyria.
Another indication for blood donation is preparation for surgery; this is an example of autologous donation. Patients preparing for surgery who are foreseen to need intraoperative or postoperative red blood cell transfusion may be directed by their surgeon or treating physician to donate blood at least 72 hours before their surgery date to have on hand for autologous transfusion during the operation or postoperatively. The patient must have adequate hemoglobin (see contraindications section below for these parameters), and the donated unit is only allowed for autologous donation. Patients with suspected bacteremia or with at-risk related conditions are contraindicated for autologous donation. The autologous donation was a widely used practice in the 1980s to 1990s due to the increased fear of transfusion-transmitted HIV and hepatitis C infections., Increased safety with blood donation, handling, screening, and transfusion practices have thankfully made transfusion-related HIV and hepatitis infections exceedingly rare; due to this and other reasons, pre-operative autologous donation has lost popularity. Patients who have common alloantibodies for which finding adequate compatible blood supply from the general population remain the most compelling case to continue autologous blood donation. Other potential benefits include preserving allogeneic blood supply, reducing the risk of alloimmunization, reducing or eliminating the risk of transmitting allogeneic infections, and promoting transfusion acceptance in certain cases. Risks associated with autologous donation include procedural induced anemia, loss of donated units due to unforeseen circumstances, and possibly delay of necessary procedures. Ironically, this may result in an increased need for allogeneic transfusion in these patients.
Another way to donate blood is through the donation of umbilical cord blood. Cord blood has a much higher percentage of hematopoietic stem cells than non-cord blood and as such is an excellent source for hematopoeitic stem cell transplantation. Cord blood is collected at the time of delivery and processed and stored in blood banks that are specifically designed for cord blood for use at a later time.
Blood donation contraindications center around donor ineligibility. These criteria are updated on the recommendation of the American Association of Blood Banks (AABB) and can be found online at any time for the most current criteria. The AABB and Food and Drug Administration (FDA)[https://www.fda.gov/BiologicsBloodVaccines/BloodBloodProducts/default.htm] should be consulted for any questions or concerns regarding current blood donation regulation and practices.
According to AABB at the time this review, to be eligible to donate blood potential donors must be at least 16 years of age (though this age may be older in some states), weigh at least 110 pounds and not be currently ill, have unregulated hypertension, diabetes, or be anemic. The donor's vital signs should also be monitored. The minimum allowable hemoglobin level for blood donation in the United States set forth by the United States Food and Drug Administration for men and women is 13.0 and 12.5 g/dL, respectively. According to the AABB, eligible donors may donate once every 8 weeks or 56 days. If a donor elects to donate two units at the same time (so-called double red cell donation), the donor may not donate red cells again for 16 weeks.
Low hemoglobin is the number one cause for donor deferral, accounting for deferral in as many as one out of 10 attempted blood donations. The causes of low hemoglobin may vary, but one of the most common is low dietary iron consumption. A large amount of iron is lost each time a person donates blood. According to one source, 56 days is insufficient time to re-build iron stores lost from blood donation in the majority of the population, and this may contribute to low-hemoglobin deferrals in repeat blood donors. Therefore, repeat donors may benefit from iron supplementation to rebuild iron stores more quickly. The amount of iron-depleted by a single donation also varies from person to person and between males and females, and the ability to replenish iron stores also differs between individuals. Infrequent donors, especially men and post-menopausal women, who are deferred for low hemoglobin may have an underlying medical condition causing the low iron and should follow up with their primary care manager for evaluation.
Contraindications to donating blood according to the AABB include:
Additionally, the AABB lists the current infectious disease testing performed on donated blood as follows:
Any donors with the above infections are deferred from blood donation. There are, however, infectious agents which may be at too low a titer to detect, may produce a false negative screening test, or for which there is not an approved test. There are also many infectious agents which are simply not tested for due to factors such as cost, availability, prevalence, etc. Unfortunately, the list of at-risk pathogens tested for in the blood supply only grows with time, adding cost to each donation event and limiting the number of eligible donors.
One of the relatively recent developments in blood donation and the practice of blood banking/transfusion is pathogen reduction or inactivation. Pathogen reduction refers to the proactive practice of eliminating potential pathogens from donated blood. Currently, the most widely used method for limiting transfusion-associated infections is testing blood for certain pathogens and removing the units (or deferring the donors) which are positive for that specific agent (a reactive process). Pathogen reduction modalities, however, target all nucleic acids in a proactive process as a means to prevent transfusion-transmitted infections. Pathogen inactivation has not been yet been adopted universally in blood banks, but in those institutions where it has been adopted, the same donor eligibility and deferral criteria regarding infection history are still enforced. Pathogen reduction, therefore, is meant to augment the prevention of transfusion-associated infection and is not used as a replacement for the testing and screening processes. There is hope that, eventually, testing and deferrals may be greatly decreased if pathogen reduction is proven to be safe and effective at removing pathogens. Pathogen inactivation holds great promise for creating a safer blood supply and even increasing the volume of the blood supply and donor pool, although concerns remain and further data and trials are required regarding cost, safety, and efficacy.
In addition, certain immunizations and medications have temporary deferral periods. The American Red Cross maintains an updated list of medications, other medical conditions and immunizations, and the necessary deferral period.
Whole blood donations are collected using sterile 16G or 18G needles and sterile collection systems which contain an anticoagulant and preservative solution for long-term blood product storage. These collection systems also have access devices to allow for sterile sample collection for later testing, without accessing the blood component storage bag. Apheresis collections, including double red cell, plasma, and platelet collection procedures, utilize technology which collects blood from the donor, processes it in a centrifuge, and retains the product of interest while returning the remaining blood components to the donor.
Most collection personnel involved in blood donation are certified phlebotomists. These personnel require a high school diploma and receive 1-2 months of classroom and hands-on training prior to becoming certified. Collection personnel may also be trained as LVNs, RNs, and EMTs, among others.
In preparation for blood donation, donors should be well rested, eat a full meal, and drink plenty of non-alcoholic, non-caffeinated beverages. Donors should refrain from heavy lifting, drinking alcohol, and smoking for several hours after donation.
After the donor screening questionnaire is completed, the donor will be evaluated by a medical receptionist. This evaluation includes an assessment of vital signs (blood pressure, pulse, temperature), an arm check looking for needle tracks and signs of injury or trauma, and a peripheral finger stick to check blood hemoglobin levels. Following the screening, the donor will proceed to the donor floor for collection. The venipuncture site will be scrubbed with a cleaning solution (either iodine or chlorhexidine), and the needle will be inserted into a peripheral (antecubital) vein in a sterile fashion. The donor is continually monitored during collection, and the needle is removed and pressure applied to the wound once the appropriate blood volume has been collected (450 ml).
Certified phlebotomists are required to perform blood donation. They are trained in the appropriate screening of potential blood donors, sterile collection methods, and management of the blood donation process. Adverse reactions are rare incidences in blood donation. The most common complication is the development of a local traumatic hematoma when the needle is removed from the vein. Holding local pressure and application of ice or cold compresses to the area can help to prevent the development or progression of hematomas. These hematomas are usually small and do not cause major problems, but rarely they can progress to cause damage to neighboring structures and tissue. Monitoring the hematoma for development of local damage is important.
Perhaps the second most common adverse side effect of blood donation is syncope, which is most often vasovagal in nature. During syncopal episodes associated with blood donation, systolic blood pressure usually falls as does the pulse. The blood donor may endorse symptoms of weakness, sweating, dizziness, or pallor. Supportive measures should be immediately taken, and the donation paused or discontinued completely. Syncope may also occur post-donation and can be avoided by requiring the donor to sit in a reclined position for a few minutes, and when able, slowly moving to the upright position and moving to an area where they should be given something to eat and drink. Increased fluid intake and avoidance of alcoholic or caffeinated beverages should be encouraged over the few hours following donation to aid replenishing lost fluid volume.,,
One study showed that first-time donor status, young age, and female gender were associated with increased risk of adverse events. Although transient syncopal events may not be dangerous themselves, injuries sustained from falls due to syncope may result. Requiring resting and sitting while donating blood and after the donation is finished is vital to preventing these injuries. Unfortunately, donors who suffer an injury during their donation may be less likely to return for a repeat donation.,
Nausea and vomiting are reported infrequently with blood donation. If encountered, supportive measures should be taken, and the donation should be paused. Overall, blood donation is a safe practice which many people view as an altruistic service they take great pride in. With little cost to themselves, they can benefit others' health care and even save lives.,
Blood donation and transfusion is a vital part of medicine in the treatment of hundreds of thousands of patients annually, and maintaining an adequate blood supply is an ongoing challenge as blood and derived blood products have limited shelf life. In the United States alone, estimates are that over 24 million whole blood and blood-derived products are transfused each year. Also, perhaps a more important factor regarding maintaining the blood supply of the future is that it is dependent solely on volunteer donors as the source (US, varies by country). Increasing restrictions on the donor pool related to infectious agents, more effective screening, the discovery of new pathogens, and changing donor eligibility and criteria are squeezing the donor supply. Fortunately, however, recent emphasis on patient blood management and appropriate blood utilization has been effective in reducing demand and maintaining adequate blood supplies for future patients in need. 
It is necessary to guard and grow the blood supply and continue to actively recruit new donors, as well as encourage the return of prior donors, to meet the medical needs of our aging population. Hospitals and other establishments continue to create campaigns and motivators aimed at increasing the donor pool. These marketing strategies often center around promoting the idea of doing good for others, meeting a real medical need, or appealing to a sense of duty and service.,, Collaboration between physicians, nurses, and allied health professionals is important for continued encouragement toward blood donation and educating others in both formal and informal settings regarding the benefits of blood donation and transfusion. During the blood donation process, protecting our blood donors from injury is not only important in and of itself but also important for preventing donor dropout and encouraging retention and recruitment.,
An Interprofessional Approach to Blood Donations
It is important to appreciate that the aged population in the US is gradually increasing. Studies from Europe reveal that this also reduces the donor pool. Further, the in-hospital need for blood has increased significantly over the past 3 decades. The younger population is often skeptical of healthcare services and may not participate in blood donation. Thus, to increase the pool of donors, an interprofessional team of healthcare workers who can educate and initiate blood donations campaigns is necessary. With changing demographics, physicians, pharmacists, nurses, laboratory technologists, and other allied healthcare workers all have an important role to play in boosting blood donations. (Level V)