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Celebrate National Blood Donor Month

January is National Blood Donor Month, which recognizes the contributions of volunteer blood donors in healthcare. You may have seen blood drives asking for donors in your community, or even given blood yourself. But what happens after a blood bank takes a donation?

A supply of donated human blood is a vital component of any healthcare system. While this might sound strange, it's necessary to keep a store of blood available at all times: patients might require a transfusion if they have bled after an injury, or if a complication requires flushing out their circulatory system. Donated blood is sent to a blood bank, where it is tested for diseases like HIV and hepatitis, and if it is disease-free, it is broken down into its main components and stored. While refrigerated red blood cells and frozen plasma can be stored for weeks or months, platelets only last about a week. Platelets help blood coagulate and form scabs to stop bleeding, and an extra supply is often needed for cancer patients and burn victims.

This is why it's necessary for blood banks to constantly receive donations, both to replenish the used supply and to replace stores that are no longer usable. While a blood donation from one person provides enough to supply three transfusions, it's unknown whether the supply will go bad before it is needed.

In addition, not all donors can give blood to all recipients. There are many different types of blood group systems, some more important than others. The most famous is the ABO system, which designates blood as being either type A, B, AB, or O depending on what type of antigens are present on the red blood cells. Before this system was discovered by the Austrian scientist Karl Landsteiner in 1900, there were many unsuccessful blood transfusions performed between people with incompatible ABO blood groups. Now, however, blood banks test for ABO groups to ensure that recipients can receive compatible blood.

Blood banks act as clearinghouses for donated blood, sending out deliveries to local clinics and hospitals for medical use. Demand can be difficult to calculate, especially in case of a large-scale emergency, so how much to store in which locations is an important, continuing question in health policy.

If you are able to, consider becoming a blood donor this January in honor of National Blood Donor Month and help save up to three lives with your donation. To learn more about blood and blood transfusions, try listening to these Science Update podcasts: Blood Cholesterol on the relationship between blood donation and cholesterol levels; Young Blood on how blood from younger people can help revive the muscles of older people; Modern Leeching on the doctors who still use leeches in medicine; Other Blood Types on new and rare blood groups; and Refreshing Blood on techniques for safer blood transfusions.

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