Blood transfusions help save millions of lives each year. Sometimes receiving a transfusion means the difference between life and death for a person, while at other times it means that people with life-threatening diseases live longer and with a better quality of life.
But what is blood transfusion? It is the transfer of blood or one of its components (red blood cells, white blood cells, platelets or plasma) from a healthy person (donor) to a sick person (recipient). With this simple action, the amount of blood in the body is increased, which allows us to improve the transport of oxygen to the organs or correct coagulation problems, among others.
But for a blood transfusion to be possible, a person must have previously donated it. Therefore, blood donation consists of extracting a small amount of blood from a donor (around 500 ml of blood).
Donation Requirements
In principle, any person of legal age in good health and weighing 50 kg or more is eligible to donate blood.
It is important, when you decide to donate, not to do it fasting, and to make sure that at least two months have passed since the last donation. It should also be noted that men can donate up to 4 times a year, while women only 3 , since women also have blood loss during their menstrual period.
Just as important is knowing who can donate and who can’t . People with hepatitis B or C, HIV or syphilis, as well as insulin-dependent diabetics, epileptics undergoing treatment or people with serious illnesses cannot donate blood.
There are also some special cases in which a person cannot donate blood temporarily , so you should wait a certain period:
- Wait 24-48 hours: flu or allergy vaccine.
- Wait 7 days: minor surgery.
- Wait 15 days: fever.
- Wait 1 month: other vaccines.
- Wait 4 months: major surgery, endoscopy, acupuncture (or similar) with non-disposable material, tattoos or earrings, after pregnancy or lactation.
- Wait 6 months: trips outside of Spain (depending on the country).
- Others: risk behaviors or activities (unprotected sex, sharing razors or toothbrushes,…)
Despite all these “yes” and “buts”, the doctor is always the one who decides whether or not to donate, depending on each case and the results of the timely medical examination.
How is the blood donation process?
The entire process of donating blood has several phases . When you go to donate they will start by asking you basic information, such as personal information or if you have had problems in previous donations, and they will make you fill out a questionnaire . Next, you will be given an interview and a basic medical examination , in which your blood pressure, pulse and hemoglobin levels in your blood will be taken (to see if you have anemia).
If everything is correct both in the questionnaire, as in the interview and the medical examination, you are considered fit to donate blood , and the donation itself proceeds.
The healthcare staff will provide you with a stretcher or a comfortable chair where you will sit during the entire blood draw, which will last about 30 minutes. Once in the chair, the extraction needle will be channeled, and the first milliliters of blood are intended for a basic blood test to assess the donor’s good health and the absence of infectious diseases, so as not to transfuse anyone with that blood if it were the case. Next, approximately 450-500 ml of blood will be extracted , which is the safe amount that can be extracted from a person weighing 50 Kg. During the extraction, the bag will remain on a scale that, while controlling the volume of drawn blood, continually agitates the blood to mix with the anticoagulants and preservatives in the bag.
And what happens after? You will ask yourself. Well, after finishing the extraction you need to rest for a few minutes, and replenish fluids by drinking lots of water and sugary products. It is also important not to drink alcohol or smoke in the two hours following the donation, and not to do intense activities or not be exposed to hot environments for at least 24 hours.
Remember that although most people are perfectly fine after a donation, there are adverse effects that must be taken into account and that can occur during or after the donation, such as dizziness, or bruising at the puncture site.
And what about that blood?
The blood is processed in the following 24 hours post-donation and the analysis carried out is examined to identify the blood group of the donor, as well as to detect possible infectious diseases such as HIV, HBV, HCV or syphilis.
As for the bag of extracted blood, it is divided into three of its fundamental components: red blood cell concentrate, plasma and platelets.
Packed red blood cells (or red blood cells) are used to treat both acute anemia secondary to blood loss and chronic anemia. They are stored at 4ºC for a maximum of 42 days.
As for plasma , it is the liquid part of the blood that contains proteins, antibodies and coagulation factors. Plasma transfusions are used to correct bleeding due to coagulation problems, or for the preparation of vaccines and some medications. This compound can be stored up to 3 years frozen.
Platelets are small cellular corpuscles that initiate the coagulation process, which is why they are often used in cancer or transplant patients, since these people usually have thrombocytopenia (decreased number of platelets). It is stored at 22 degrees for no more than 7 days.
The different blood groups
The blood group is a classification system of human blood , and two forms of classification can be differentiated that complement each other.
The first is known as ABO , and is based on the type of antigens that a person’s red blood cells possess. In this way, a person with A antigens on their red blood cells, and anti-B antibodies in their plasma, will be of blood group A. If, on the contrary, the antigens are type B and the anti-A antibodies, their group blood group will be B, while if you have both antigens (A and B) you will have a type AB blood group, and if you do not have any type of antigens in your red blood cells but have anti-A and anti-B antibodies in your plasma, you will belong to type AB. group 0 (zero).
On the other hand, there is another classification system based on Rhesus factors, or more commonly known as Rh . The Rh is another type of antigen that may or may not be linked to the blood, so that if the person has this type of antigen, it will be labeled as Rh positive, while if it lacks them, it will be Rh negative.
Knowing this we can differentiate 8 blood groups in total : A+, A-, B+, B-, AB+, AB-, 0+ and 0-. If we take into account that antibodies attack antigens of the same type (anti-A antibodies attack A antigens) and that Rh- can donate to Rh+ but not vice versa, we can ensure that 0- is the universal donor and the AB+ the universal receiver .
Difference between blood donation and plasma donation
As we have already said, blood donation is the act of giving blood altruistically and voluntarily to people who need it . Normally, when people talk about blood donations, they refer to the donation of whole blood, that is, in which all blood components (red blood cells, white blood cells, platelets and plasma) are donated.
Even so, there is another type of donation in which only the plasma is included, called plasmapheresis . There are few differences between the donation of blood and plasma in terms of donation requirements, but it must be taken into account that plasma can be donated every 15 days up to a total of 24 times a year , since that the recovery of the plasma is very fast and in a few days we are as good as new.
One of the crucial differences in plasma donation, compared to blood donation, is the use of an apheresis machine , which is used to separate plasma from whole blood and return the rest of the components (red blood cells, white blood cells and platelets) to your body back. For this reason, the plasma donation lasts longer , approximately one hour.
It is also important to know that, in many centers, an appointment is needed before going to donate, since the plasma extraction machines are limited.
References
Beurel, A., Terrade, F., Lebaudy, J. P., & Danic, B. (2017). Determinants of plasma donation: A review of the literature. Transfusion clinique et biologique, 24(3), 106–109. https://doi.org/10.1016/j.tracli.2017.06.001
Red Cross Blood Donation Center. https://www.donarblood.org/
Chauhan, R., Kumar, R., & Thakur, S. (2018). A study to assess the knowledge, attitude, and practices about blood donation among medical students of a medical college in North India. Journal of family medicine and primary care, 7(4), 693-697. https://doi.org/10.4103/jfmpc.jfmpc_54_17
Enawgaw , B. , Yalew , A. , & Shiferaw , E. (2019). Blood donors’ knowledge and attitudes towards blood donation at North Gondar District Blood Bank, Northwest Ethiopia: a cross-sectional study. BMC Research Notes, 12(1), 729. https://doi.org/10.1186/s13104-019-4776-0
Guglielmetti Mugion, R., Pasca, M. G., Di Di Pietro, L., & Renzi, M. F. (2021). Promoting the propensity for blood donation through the understanding of its determinants. BMC health services research, 21(1), 127. https://doi.org/10.1186/s12913-021-06134-8
Gyuris, P., Gáspár, BG, Birkás, B., Csókási, K., & Kocsor, F. (2021). Help Is in Your Blood-Incentive to “Double Altruism” Resolves the Plasma Donation Paradox. Frontiers in psychology, 12, 653848. https://doi.org/10.3389/fpsyg.2021.653848
