Blood donation

In some countries, established supplies are limited and donors usually give blood when family or friends need a transfusion (directed donation).

Many donors donate for several reasons, such as a form of charity, general awareness regarding the demand for blood, increased confidence in oneself, helping a personal friend or relative, and social pressure.

The donor must also answer questions about medical history and take a short physical examination to make sure the donation is not hazardous to their health.

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.

When a person has blood stored that will be transfused back to the donor at a later date, usually after surgery, that is called an autologous donation.

[10][11][12] The World Health Organization gives recommendations for blood donation policies,[13] but in developing countries many of these are not followed.

For example, the recommended testing requires laboratory facilities, trained staff, and specialized reagents, all of which may not be available or too expensive in developing countries.

These can occur at a blood bank, but they are often set up at a location in the community, such as a shopping center, workplace, school, or house of worship.

[20] Historically, in the United States donors were segregated or excluded on race, religion, or ethnicity, but this is no longer a standard practice.

[29] Donors are examined for signs and symptoms of diseases that can be transmitted in a blood transfusion, such as HIV, malaria, and viral hepatitis.

[8] The donated blood must be irradiated to prevent a potentially deadly graft-versus-host disease, which is more likely between genetically related people.

[8] It is a common misconception that directed donations are safer for the recipient; however, family members and close friends, especially parents who have not previously donated blood, frequently feel pressured into lying about disqualifying risk factors (e.g., drug use or prior sexual relationships) and their eligibility, which can result in a higher risk of infection with bloodborne pathogens.

The donor is also examined and asked specific questions about their medical history to make sure that donating blood is not hazardous to their health.

[38] Donors with aortic stenosis have traditionally been deferred out of concern that the acute volume depletion (475 mL) of blood donation might compromise cardiac output.

[54] The blood is usually stored in a flexible plastic bag that also contains sodium citrate, phosphate, dextrose, and adenine.

This was a development of the dried plasma used to treat the wounded during World War II and variants on the process are still used to make a variety of other medications.

[81] Blood centers typically provide light refreshments, such as orange juice and cookies, or a lunch allowance to help the donor recover.

[56] In hot climates, donors are advised to avoid dehydration (strenuous exercise and games, alcohol) until a few hours after donation.

[83] Red blood cells are replaced by bone marrow into the circulatory system at a slower rate, on average 36 days in healthy adult males.

[citation needed] Plasmapheresis and plateletpheresis donors can donate much more frequently because they do not lose significant amounts of red cells.

Manual apheresis is extremely rare in the developed world because of this risk and automated procedures are as safe as whole blood donations.

[50] Plasma can be stored frozen for an extended period of time and is typically given an expiration date of one year and maintaining a supply is less of a problem.

[113] Blood donations tend to always be high in demand with numerous accounts repeatedly stating periodic shortages over the decades.

The subject was discussed at length after the September 11 attacks in the United States, and the consensus was that collecting during a disaster was impractical and that efforts should be focused on maintaining an adequate supply at all times.

[124] Multiple studies have shown that the main reason people donate is due to prosocial motivators (e.g., altruism, selflessness, charity), general awareness regarding the demand for blood, increased confidence in oneself, helping a personal friend/relative, and social pressure.

[128] Donating blood may reduce the risk of heart disease for men, but the link has not been firmly established and may be from selection bias because donors are screened for health problems.

[132] The World Health Organization set a goal in 1997 for all blood donations to come from unpaid volunteer donors, but as of 2006, only 49 of 124 countries surveyed had established this as a standard.

[134] In some countries, for example Brazil and the United Kingdom, it is illegal to receive any compensation, monetary or otherwise, for the donation of blood or other human tissues.

[138] Blood centers will also sometimes add incentives such as assurances that donors would have priority during shortages, free T-shirts, first aid kits, windshield scrapers, pens, and similar trinkets.