Why are Blood Donations so Important?

There are four major groups of blood determined by the presence or absence of an antigen* on the surface of the red blood cell [1].

1. Blood type A = presence of antigen A.

2. Blood type B = presence of antigen B.

3. Blood type AB = presence of both antigens, A and B.

4. Blood type O = no antigen present.

In addition to these antigens, another protein called Rh factor can also be present (+) or absent (-). Therefore, the 8 most common blood types are: A+, A-, B+, B-, O+, O-, AB+, and AB- [1]. 

To have a safe transfusion and prevent a negative reaction, it is very important to match both blood and plasma. In general, the donated blood must lack the same antigens that the recipient lacks to avoid an immune system response [1,2]. When an incompatibility occurs, the antibodies attach to the red blood cells and clump them together, which stops blood supply and causes strokes [2-4]. The table below represents the compatibility in blood types between donors and recipients.

Check out the Red Cross website here to further understand the compatibility between different blood types, how blood type is genetically determined, and the percentages of a certain population’s blood type [1].

Blood type O is usually short in supply and high in demand. This is because O- is the universal donor and is used most often during emergencies, and O+ is the most common blood type (37% of the population) [1]. Approximately, 51% of African-Americans and 57% of Hispanics have blood type O, playing a critical role in blood supply. 

Additionally, there are also rare blood types, and because blood type is inherited, often a compatible donor is someone with a similar ethnic background. For example, U-negative and Duffy-negative blood types are unique to African Americans, making it more difficult for some people to find their blood type as they can only rely on African-American donors for transfusion [5]. Therefore, it is extremely important to increase the number of donors from all ethnic and racial groups.

Some rare blood types by ethnic groups [5]. 

Even though the need for blood is constant, especially since there is no artificial substitute for it, only about 3% of people donate blood yearly [6]. We need these numbers to go up! Blood transfusions are given to patients in many situations. Donated blood can be used as transfusions for blood loss during surgery or traumatic injuries, for cancer patients after chemotherapy, for patients suffering from chronic diseases, and more. You can read some stories of how blood donations can save lives here [7]. Many lives can be saved from only one donation!

To learn more information about the steps taken for blood donation during COVID–19 or how the blood is stored and used after a donation is made, stay tuned for the next posts!

*Antigen - a molecule produced by immune cells that recognizes and binds to another molecule that is foreign to the organism, the antigen. By binding to the antigen, the antibody can tag the foreign molecule for destruction or directly neutralizes it.

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Written by: María

Edited by: Natasha

BioDecoded is a volunteer group committed to sharing accurate scientific information. For more information about vaccines or other scientific processes, please see previous posts or consult with your personal physician. If you have any questions about this topic, please comment or send them to our email.

References:

1. Blood Types (2022). Red Cross. Available at: https://www.redcrossblood.org/donate-blood/blood-types.html (Accessed: 3 November 2022).

2. Dean, L. Chapter 3: Blood transfusions and the immune system (2005). National Center for Biotechnology Information (US). Available at: https://www.ncbi.nlm.nih.gov/books/NBK2265/(Accessed: 3 November 2022).

3. Hemolytic transfusion reaction (2022).  MedlinePlus Medical Encyclopedia. Available at: https://medlineplus.gov/ency/article/001303.htm#:~:text=Blood%20transfusions%20between%20incompatible%20groups,cells%2C%20causing%20them%20to%20burst. (Accessed: 3 November 2022).

4. ABO Incompatibility Reaction: Causes, Risk Factors & Symptoms (2022). Healthline. Available at: https://www.healthline.com/health/abo-incompatibility (Accessed: 3 November 2022).

5. Blood and Diversity (2022). Red Cross. Available at: https://www.redcrossblood.org/donate-blood/blood-types/diversity.html (Accessed: 3 November 2022).

6. Why Blood Donation is Important (2022). Red Cross.Available at: https://www.redcrossblood.org/local-homepage/news/article/blood-donation-importance.html#:~:text=Blood%20is%20essential%20to%20help,eligible%20people%20donate%20blood%20yearly (Accessed: 3 November 2022).

7. How Blood Donations Help (2022). Red Cross. Available at: https://www.redcrossblood.org/donate-blood/how-to-donate/how-blood-donations-help.html (Accessed: 3 November 2022).