Everything about blood donation and transfusion

Blood is the most precious gift that anyone can give to another person. Blood donation is a living donation. Your decision to donate blood can save the life of one or more people.

Millions of people worldwide need blood transfusions every year, and our donated blood can save their lives. Follow our article to learn about this humanitarian action.

Because blood storage time is limited, there is a constant need for regular blood donation. Regular blood donation by a sufficient number of healthy people is essential to ensure that healthy blood is available at any time and place. Of course, in the current situation, the amount of donated blood is much less than the global demand for blood, and some countries in the world are in a critical situation in this regard.

 An overview of blood and its components

Blood is essential for the transport of various substances to tissues throughout the body. Blood is a life-sustaining fluid circulating throughout the body and carries various substances such as electrolytes, hormones, vitamins, antibodies, nutrients, heat, oxygen, and immune cells to various tissues. Blood also removes waste products and carbon dioxide from body tissues. The components of human blood are:

Plasma: The fluid part of the blood in which the following blood cells are suspended:

  1. Red blood cells (erythrocytes)
  2.  White blood cells (leukocytes): Different types of white blood cells include:
  • Lymphocytes
  • Monocytes
  • Eosinophils (acidophiles)
  • Basophils
  • Neutrophils

Granulocytes are a group of white cells with granules in their cytoplasm (including neutrophils, eosinophils, and basophils).

  1. Platelets (platelets)

Blood cells are made in the bone marrow. Bone marrow is an explosive substance located in the bones that make up all blood cell types. There are other organs and systems in our body that help regulate blood cells. Lymph nodes, spleen, and liver help regulate these cells’ production, destruction, and function. The production and development of new cells in the bone marrow is a process called hematopoiesis.

Blood cells that form in the bone marrow, primarily stem cells. The stem cell is the first stage in the formation of all blood cells. As stem cells mature, several distinct types of blood cells are formed, including red cells, white cells, and platelets. Immature blood cells are also called blasts. Some blasts remain in the bone marrow until they mature. Others migrate to other parts of the body, where they mature into functional blood cells.

What are the functions of blood cells?

The primary function of red blood cells, or erythrocytes, is to carry oxygen from the lungs to the body’s tissues, remove carbon dioxide from the tissues and return it to the lungs. Hemoglobin is an essential protein in red blood cells that carries oxygen from the lungs to all parts of the body.

The job of white blood cells or leukocytes is to fight infection. Different types of white blood cells have a unique role in fighting bacterial, viral, fungal, and parasitic infections. These cells protect you from foreign objects entering the bloodstream, such as allergens, and also play a role in protecting against mutant cells such as cancer.

The primary function of platelets or platelets is to clot blood. Platelets are much smaller in size than other blood cells. They come together to form plaques in the bloodstream to stop bleeding.

Blood donation

Blood donation is a voluntary procedure that can save the lives of people who have lost a lot of blood due to accidents or surgery and people who are very anemic due to certain diseases or treatments or have very low platelet counts. Millions of people around the world need blood transfusions every year. There is no substitute for human blood. In all blood transfusions, the blood of a human donor is used.

If the body loses one or more of the components that make up healthy blood, a blood transfusion can replenish what the body has lost. Depending on the amount of blood needed, a blood transfusion can take one to four hours.

Screening measures help maximize the safety of donated blood for the donor and recipient. The criteria for donating blood vary slightly between centers and countries.

The reason for the need for blood transfusions

A person may need a blood transfusion for many reasons. Some of them are:

  • The person has significant surgery or severe injury, and the lost blood must be replaced.
  • The person has gastrointestinal bleeding due to ulcers or other factors.
  • A person has a disease such as leukemia or kidney disease that causes anemia (anemia: lack of a sufficient number of healthy red blood cells).
  • The person has been treated for cancer, such as radiation or chemotherapy.
  • A person has a blood disorder such as severe liver problems.

Types of blood donation

Several types of blood donations can help meet different medical needs.

Whole blood donation: Whole blood donation is the most common type of blood donation during which a person can donate a unit of whole blood. Then the blood components are separated: red blood cells, platelets, and Plasma.

Apheresis: individual components of the blood can be collected. Apheresis allows selective collection of red blood cells, platelets, Plasma, and granulocytes. In this procedure, a needle is inserted into each arm. The blood is drawn through a needle through a device that separates the Plasma from individual blood cells, preserves the components, and returns the rest of the blood to the donor through another needle. During this process, more than one component of blood can be collected. The time it takes to do this is longer than the time required to donate whole blood, and it usually takes up to 2 hours. Apheresis may be performed to collect different cells:

  1. Red Blood Cells (Double Red Cell Donation): Donors can donate their red blood cells every 16 weeks through apheresis. This procedure removes many red blood cells; it takes longer to replace them (than a whole blood donation). In this method, the red blood cells that a person donates are twice as large as a total blood donation. Red blood cells carry oxygen throughout the body. People who need red blood cells have lost a lot of blood (for example, during an accident or injury) and have anemia with severe symptoms.
  2. Platelets: In this method, only platelets are collected. Platelets are cells that help stop bleeding by accumulating and forming clots in blood vessels. Donated platelets are usually given to people with leukemia, people undergoing chemotherapy, and infants with severe infections. Donors can donate their platelets up to 24 times a year. About one percent of people have a mild reaction to a substance (citrate) that mixes with blood during a platelet donation. This reaction can include numbness and tingling, muscle cramps, and nausea. This reaction can be prevented by taking calcium supplements before or during donation.
  3. Plasma: In this procedure, the fluid portion of the blood (Plasma) is collected. Plasma helps blood clot and contains proteins and other substances such as electrolytes that help the body function naturally. Plasma is usually given to people with severe liver problems, burns, and bacterial infections of the blood.
  1. Granulocytes: These cells are a group of white blood cells that fight infection. Granulocyte donors may be given a granulocyte colony-stimulating factor (G-CSF) and a glucocorticoid drug called dexamethasone the day before donation to increase the number of granulocytes in the blood. Glucocorticoids are not usually given to people with diabetes, peptic ulcers, or glaucoma. G-CSF and dexamethasone’s side effects may include headache, joint pain, fatigue, insomnia, allergic reactions, and fever.


Autologous blood donation: Autologous blood donation or’s blood donation is a situation in which the person to be operated on donates his blood for use a few weeks before the surgery. Autologous blood donation reduces the risk of (but not all) infectious problems associated with blood transfusions.

Requirements for blood donation

In general, you must meet the following conditions to donate blood:

  • Proper health status
  •  Appropriate age for blood donation, which is 16 to 18 years (depending on the region)
  • Minimum weight of 50 kg
  • Confirmation in the physical assessments and health history described below

Things to consider before donating blood:

  • Get enough sleep the night before donating blood.
  • Eat a healthy meal before donating blood.
  • Avoid fatty foods such as hamburgers, French fries, or ice cream before donating blood. Infection tests performed on donated blood can be affected by the blood’s fats after eating fatty foods.
  • Drink about half a liter of water or other fluids before donating blood.
  • If you are a platelet donor, keep in mind that you should not take aspirin two days before donating.

Procedures performed before the blood donation procedure at the relevant medical center:

Before donating blood, the donor is asked to complete a medical questionnaire that includes questions about behaviors that increase the risk of blood-borne infections. This information is kept confidential. A brief physical examination is also performed, which includes blood pressure, pulse, and body temperature. A small blood sample is taken from the finger and used to check the level of hemoglobin. If the donor’s hemoglobin concentration is average and meets other requirements, they can donate blood.

Blood donation procedure

During a blood donation, the donor sits comfortably in a chair, and a needle is inserted into his or her arm to draw blood. This is done slowly to minimize possible symptoms such as lightheadedness. One unit of blood is removed (about 450 ml). During the blood donation process, the person is monitored.

According to FDA regulations, blood donors should not donate blood again for 56 days (8 weeks) after donation. Of course, not all donors can regain their blood donation status during this time because it depends on how quickly the body replaces its red blood cells. For example, women who have heavy periods cannot donate blood every 56 days because their iron stores are not enough to replenish lost red blood cells.

Blood donation causes iron to be removed from the body, and if the lost iron is not replaced before the next donation, it will lead to iron deficiency. The risk of iron deficiency is higher in adolescent donors, premenopausal women, and people who bleed frequently. Because the strategy of consuming iron-rich foods is not enough to replace lost iron, it is recommended that people at risk for iron deficiency take a multivitamin containing iron or an iron supplement for about 60 days after donating blood.

What to do after donating blood:

  • Drink more fluids for a day or two.
  • Avoid strenuous activity or lifting heavy objects for up to 5 hours after donating blood.
  • If you feel light-headed, lie down, and put your feet up until the feeling disappears.
  • Please do not remove the bandage from your arm and keep it dry for 5 hours.
  • If you are bleeding after removing the bandage, apply pressure to the bleeding area, and raise your arm until the bleeding stops.
  • If your arm hurts, use a painkiller such as acetaminophen. Avoid taking aspirin or ibuprofen for the first 24 to 48 hours after donating blood.
  • If you forget to report any important health information before donating or have a specific medical problem, contact your blood donation center.

If you have any of the following symptoms, you should contact the relevant center:

  • Persistent nausea, lightheadedness, and dizziness after resting, eating, and drinking fluids
  • Persistence of pain, bleeding, and bulging after removal of the bandage at the needle site.
  • The feeling of pain or tingling that goes from the arm to the fingers

Signs and symptoms of a cold or flu, such as fever, headache, or sore throat, within four days of donating blood

Bacterial infections can be transmitted through blood donation to the recipient, so you should tell the center if you become ill so that your blood will not be used.

Tests: Blood type determination

The blood given to the recipient must be compatible with their blood type; Otherwise, the antibodies in the recipient’s blood will attack them and cause problems. Donated blood is tested to determine blood type (classified as A, B, AB, or O) and Rh factor. Rh factor indicates the presence or absence of a specific antigen in the blood. If a person has this antigen, his blood is Rh-positive, and if he does not have this antigen, his blood is Rh-negative. This information is essential because the type of blood type and Rh factor must match the type of blood type and Rh factor of the person receiving the blood. Forty percent of people have blood type O, which is almost safe to pass on to anyone. If you have this blood type, you are a public donor. If your blood type is AB, you can receive any blood type, and you are considered a general recipient. If your blood is Rh-negative, you can only get Rh-negative blood.

The figure above shows the possible compatibility in blood transfusion between donor and recipient based on ABO and Rh systems.

Measures to protect the donor

Numerous measures are taken to ensure that blood donation is safe for the donor, and thus, blood donation is unlikely to have adverse effects on the donor’s health.

Review of medical history: All blood donors are asked questions about their medical records to determine if they can donate blood without any risk or experience.

Heart, Lung, and Blood Diseases: Donors are asked if they have ever had heart, lung, or blood disease. Accordingly, patients with heart disease, heart valve problems, irregular heartbeat, cerebrovascular disease, brain failure, and certain lung diseases may be exempt from donating blood or may be able to donate blood under certain conditions. Some blood disorders, such as iron deficiency anemia or chronic leukemia, may also be ruled out.

Feeling healthy: Donors are asked if they feel healthy on the day of the blood donation.

Seizures: People who have a history of seizures can donate blood as long as they do not have seizures for a certain period (usually six months).

Recent surgery: People who have recently had surgery can donate blood when they recover and resume full activity. Of course, if a blood transfusion was performed during the surgery, that person cannot donate blood for up to a year.

Pregnancy: Pregnant women are not allowed to donate blood during pregnancy and up to 6 weeks after the end of pregnancy.

Age requirements: The minimum age for blood donation is 16 or 18 years old (depending on the country’s law). There is no age limit for donation in most cases, although some materials require the donor’s doctor’s approval.

Weight requirements: People weighing less than 50 kg are not allowed to donate blood. The lower the donor’s weight, the greater the likelihood of a reaction such as dizziness and fainting after donating blood.  (12 Ways To Prevent Overeating After Exercise)

Most blood centers perform another assessment of people between the ages of 16 and 18 who are just above the weight range, in which the donor’s blood volume is estimated based on his or her height and weight. There is usually no limit to the maximum weight of a donor.

The blood donor is also asked questions about whether the blood transfusion is safe for the blood recipient. One of these is the possibility of infections that are transmitted by blood.

Medical evaluation: In addition to medical history, donors undergo a brief physical examination before donation to check for obvious signs of illness or conditions that could lead to a disqualified donor.

Vital Signs: The donor’s pulse, blood pressure, and body temperature are measured before donating blood. People who have a fever, high blood pressure, a very high or meager heart rate (except very fit athletes and people taking beta-blocker drugs), or an irregular heartbeat are temporarily not allowed to donate blood.

Blood test: A small sample of blood is taken from the fingertip and used to check the number of red blood cells or hemoglobin in the blood. This will ensure the donor does not have anemia or does not have anemia after donating blood. People with deficient hemoglobin levels are temporarily not allowed to donate blood.

Screening measures to protect the recipient

Screening blood donors help ensure that donated blood is safe to transmit to the recipient. In this regard, the donor is asked to complete a questionnaire, and laboratory tests are performed to assess the possibility of possible infections in the donated blood.

Infection screening

Human Immunodeficiency Virus (HIV): This virus is the virus that causes AIDS. Various measures are taken to screen blood donors for HIV infection and other risk factors for HIV. These include completing questionnaires about any signs and symptoms of HIV and behaviors that increase the risk of HIV infection. Such behaviors include using over-the-counter injecting drugs, having unprotected sex, or having sex in exchange for money or drugs. Depending on the answers to these questions, a person may not be allowed to donate blood or may have to wait a while before donating blood.

No one should donate blood to test blood for HIV and other sexually transmitted infections. Even if the donated blood is tested for HIV infection, these tests are incomplete, and there is a small chance that an HIV-infected person will be able to transmit the virus to a recipient if they donate blood. Free and anonymous tests for HIV are available.

Hepatitis: Hepatitis is a viral infection that causes inflammation of the liver. Blood donors are screened for whether they are exposed to (or infected with) hepatitis B or C viruses. People who have had sex with or lived in the same place as patients with hepatitis are not allowed to bleed for 12 months after the last exposure.

People who have had a positive hepatitis B virus surface antigen-antibody test (a marker for hepatitis B virus infection) are permanent without blood donation status. However, hepatitis B vaccination may temporarily test positive for this test. To avoid being disqualified as a blood donor, a person who has recently received the hepatitis B vaccine must wait 21 days before donating blood.

People who receive blood are not allowed to donate blood until 12 months after the date of the blood transfusion. In some countries, people who get tattoos are not allowed to donate blood until 12 months after the tattoo. Blood donation is allowed in many areas where the tattoo industry is strictly regulated without a waiting period. There are similar rules for body piercing.

Zika virus: Zika virus causes a mild infection in most people, but if a pregnant woman becomes infected with the virus, it can cause miscarriage or severe fetal brain abnormalities. If the blood donor has previously traveled to areas of the world where the virus is prevalent, blood transfusion officials should consider this.

Malaria: Malaria transmission through blood transfusions is standard in some parts of the world. People with malaria are not allowed to donate blood until three years after the symptoms go away. Travelers to areas where malaria is common are not allowed to donate blood until one year after leaving the area, provided they have no signs of malaria. Immigrants or residents of countries where malaria is prevalent are not allowed to donate blood until three years after leaving the country.

Chagas and Babesia diseases: Blood donors are asked if they have ever had Chagas disease (American trypanosomiasis), and most blood donors are tested for Chagas disease. Transmission of Babesia (a malaria-like disease transmitted by ticks) is not expected through blood transfusions. Donors are asked if they have ever had the disease. In areas where Babesia is more prevalent, blood may be tested.

Prion Diseases: Krutzfeldt-Jakob disease (CJD) is a rare but deadly neurological disease. Krutzfeldt-Jakob variant (vCJD) is a related disease but pathophysiologically a separate disease that first appeared in the UK in 1996. Affected people may not have any symptoms of CJD or vCJD for years. The infectious agent of both protein diseases has an odd twist called a prion. Despite this shallow risk of vCJD, those who have been in the UK for three months or more from 1980 to 1980 are not allowed to donate blood.

Bacterial infection: Some bacteria live naturally on the skin and in the gastrointestinal tract. Bacteria can enter the donated blood if:

  • The blood donor has a blood infection.
  • If bacteria on the skin enter the bloodstream through a needle
  • If there is a skin infection near the site where the blood is drawn

To reduce the possibility of bacterial contamination of the blood. The skin around the site is carefully examined and cleaned before inserting the needle.

Donors who have a fever, do not feel healthy, or people who take oral antibiotics (except to treat acne) are not allowed to donate blood. These restrictions also apply to people who store blood for their use.

Other Infections: Donated blood cannot be tested for any possible infections, and new types of infections are becoming more common around the world. Before donation, training materials are provided to donors. The donor completes questionnaires containing several general questions to identify people with infection symptoms or traveled to areas where these infections are common. Also, blood centers ask donors to notify the blood donation center if they develop specific medical symptoms within two weeks of donation.

Other medical conditions

To protect the blood recipient from non-infectious problems. The donor is evaluated before donating blood for specific medical conditions, such as the following.

Cancer: There have been no reported cases of cancer transmitted by blood transfusion. However, because such a transfer is theoretically possible, the history of donor cancer is examined. Donors with solid tissue or limb cancer (such as lung, liver, breast) are allowed to donate blood if they have been free of cancer and symptoms for a period to be determined by the blood collection center. This time is variable but at least one year.

  • Donors with leukemia (such as leukemia or lymphoma) are permanently disqualified from donating blood.
  • Donors with superficial cancer that has been entirely removed by surgery (such as basal cell carcinoma of the skin or early-stage cervical cancer) can donate blood without waiting.

Hemochromatosis: People with inherited hemochromatosis (a condition whose standard treatment is repeated blood draws) can donate their blood if they meet other blood donation criteria and FDA-specific blood bank regulations are followed. There is no risk of transmitting hemochromatosis to the recipient.

Recent Vaccinations: There are strict standards for when you can donate blood after vaccination. When you donate blood, you are asked if you have recently received the vaccine. If you have been vaccinated, you may have to delay donating blood. For some live or attenuated viral or bacterial vaccines (such as measles, mumps, polio, and yellow fever), you should wait at least two weeks before donating blood. You will have to wait four weeks for rubella or varicella-zoster vaccines.

Medications: Most medications taken by donors do not pose a risk to recipients. However, several medications can cause congenital disabilities and are considered during blood donor screening. These drugs include:

  • Etretat (treatment of psoriasis)
  • Acitretin (treatment of psoriasis)
  • Isotretinoin (acne treatment)
  • Finasteride (treatment for benign prostatic hyperplasia or hair loss)
  • Dutasteride (treatment of enlarged prostate)
  • Vismojib (treatment of skin stem cell cancer)

Donors taking isotretinoin and finasteride are asked to wait until one month after the last dose before donating blood. Donors who have taken Dutasteride will have to wait six months. Donors who have taken Wismojib will have to wait two years, and those who have taken acitretin will have to wait three years. People who have taken etretinate can never bleed.

People who have taken aspirin or aspirin-containing medications in the past 48 hours can donate whole blood but cannot donate platelets during apheresis. People who have taken antiplatelet drugs should wait 2 to 14 days before donating platelets through apheresis.

People who have used anticoagulants (blood thinners) are generally not allowed to donate blood for at least 2 to 7 days (depending on the medication type) after the last dose. Some anticoagulants include warfarin, dabigatran, rivaroxaban, apixaban, edoxaban, and heparin.

Donated blood laboratory tests

After a unit of blood is donated, the blood is tested for infectious diseases that can be spread by blood transfusions. These tests include HIV infection, hepatitis B, hepatitis C, human lymphotropic T virus (HTLV), West Nile virus, Zika virus, Chagas disease, and syphilis. If these tests’ results are negative, blood will be distributed for use in hospitals and clinics. If any of these tests are positive, the blood center will notify the donor, and the blood will be discarded.

After donating blood, donors are usually given a phone number to report any factors that may affect their blood use or signs of infection within the first two weeks after donating blood (such as symptoms of an upper respiratory tract infection). Gastrointestinal disease or infection caused by a virus transmitted by mosquitoes). Such reports will be evaluated, and the blood unit may be discarded.

Possible complications of blood donation

Most people who donate blood do not have complications that require medical attention. The most common complications include pain or bruising at the needle site and fatigue. A small percentage of people (2 to 5%) feel weak before, during, or after a blood donation. This condition is more likely to occur in donating blood for the first time and in younger people. Drinking half a liter of water before donating blood helps prevent this condition.

Risks of blood donation

Blood donation is safe. Disposable sterile equipment is used for each donor, so there is no risk of contracting a blood-borne infection through blood donation. If you are a healthy adult, you can donate a unit of blood without risking your health. Within 24 hours of donating blood, the body replaces lost fluids, and within a few weeks, red blood cells regenerate.

Risks and complications of blood transfusion

Blood transfusions are generally considered safe, but there are possible complications. Sometimes some side effects occur quickly, and some side effects take some time to show up.

Fever due to fever-causing hormones (cytokines): This is called a non-hemolytic reaction to transfusion fever (FNHTR). Accumulation of cytokines during cellular components’ storage (especially in platelet units) is thought to be the most common event leading to FNHTR symptoms. Cytokines are released by white blood cells, and depletion of leukocytes before storage reduces this risk.

It is not a serious problem to have a fever within 1 to 6 hours after receiving blood, but if nausea and chest pain is dangerous, you should immediately see a doctor.

Allergic reactions to proteins and cells in donated blood: Even if the type of blood transfused is compatible with the recipient’s blood, an allergic reaction may occur in the recipient’s body to the transfused blood. In this condition, the person suffers from itching and hives.

Anaphylactic reaction: This reaction occurs within minutes of the onset of transmission and may even be fatal. The person may experience swelling of the face and throat, shortness of breath, and low blood pressure.

Hemochromatosis (iron overload): If a person has multiple blood transfusions, too much iron may accumulate in their blood. This can damage the heart and liver.

Shortness of breath due to immune / inflammatory reactions known as acute transfusion-related lung injury (TRALI)  This reaction is infrequent but potentially fatal. It appears in the form of fever and low blood pressure within a few hours after the onset of transmission. TRALI damages the lungs. This condition is caused by antibodies or other substances in the new blood.

Shortness of breath due to a large volume of fluid known as AC (TACO)

Host Transplant Disease: Infection of the recipient’s immune system by transplanted cells is called transfusion host disease. This condition usually occurs in receptors with defective immune systems in which their immune system is unable to detect injected T lymphocytes as an external agent. These lymphocytes in the recipient’s body react to the host. This complication is infrequent but usually fatal. This condition occurs when new white blood cells invade the bone marrow of the recipient. If a person has a weak immune system, they are more likely to develop this complication.

Acute immune hemolytic reaction: This complication is rare but is a medical emergency. In this reaction, due to blood incompatibility, the recipient’s immune system attacks the blood cells in the blood received. This usually happens during or after the transfer, and the person develops symptoms such as fever, chills, nausea, or pain in the chest and lower back. The color of the urine may also be dark.

Hemolytic delayed reaction: This condition is similar to the above but occurs gradually.

These risks are not very common and are well known to physicians, and measures are usually taken to minimize them.

Risk of infection through blood transfusion

Safety measures such as advanced screening tests significantly reduce the risk of contracting a viral infection through blood transfusions. Blood banks screen donors and test donated blood for infections with viruses, bacteria, and parasites; However, infections are also a rare possibility that may occur with blood transfusions. These infections are less likely to be transmitted through blood transfusions than the risk of dying in a car accident or being killed by a firearm. Recent estimates suggest that the risk of certain infections after receiving a unit of blood is as follows:

Disease Probability of contracting a blood transfusion
Hepatitis B 1 In 200,000 to 1 in 360,000 cases of blood transfusion
Hepatitis C 1 in 1 million to 1 in 2 million
HIV 1 in 1.5 million to 1 in 2 million
HTLV 1 in 2 million

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