Explaining blood transfusions

Ruby was feeling worn out, tired, run-down, wiped out — and when she moved too quickly, she had to catch her breath; she also had mild chest pain. She went to her doctor, who ran a series of blood tests. Ruby was so badly anemic that she needed a blood transfusion.

She wasn’t even sure what that was.

Blood Transfusions

A blood transfusion is a common procedure, where you receive donated blood through an IV line inserted into a blood vessel. Generally, the process takes around two hours, depending on how much blood you need.

You may need a blood transfusion if you lost blood due to:

  • Surgery
  • Accident
  • Injury

Sometimes you may have an illness where you no longer make blood properly. Some medications, including some chemotherapy drugs, can interfere with your blood-producing capabilities.

“We’ll first run a thorough analysis of your blood, typing for the ABO blood group and screening for antibodies to these other common antigens before we transfuse you.”

Walter J. Linz, MD, Medical Director of the Scott & White Blood Center and Transfusion Medicine, explains blood transfusions.


“Why do we give people red blood cells? There’s only one reason to give red blood cells and that’s to increase the oxygen-carrying capacity. If you’re anemic, you don’t have enough red blood cells to move oxygen from your lungs to your peripheral tissues,” explains Dr. Linz.

Your blood carries oxygen and nutrients — as well as medication — to the cells throughout your body. An abundant blood supply is necessary to healing and good health.

Blood Transfusions and Blood Type

“By convention, when we ask someone what his blood type is, we’re talking about the ABO system. That was discovered in 1901. It was the first system, and it contains the blood types A, B, AB and O, which we refer to as the ABO blood group,” explains Dr. Linz.

“There is also the Rh system, which was discovered in 1929. The Rh system is composed of 49 antigens, but we talk only about one antigen, and that’s the D antigen. So when people talk about whether they’re Rh-positive or Rh-negative, they’re talking about one antigen out of a group of 49 antigens,” says Dr. Linz.

There are 24 total blood systems, including such systems as Kell, Kidd and Duffy with more than 500 identified antigens. An antigen is actually a carbohydrate or protein on the surface of the red blood cell.

If you’re receiving a non-emergent blood transfusion at Scott & White, we’ll first run a thorough analysis of your blood, typing for the ABO blood group and screening for antibodies to these other common antigens before we transfuse you, Dr. Linz says.

In the event of emergencies, Dr. Linz says, you’ll be transfused with group O blood. Group O is the universal donor.

“Also, if you’re a young woman, all efforts will be made,” Dr. Linz says, “to also transfuse Rh-negative blood as well. ‘Negative’ means it doesn’t contain the Rh D antigen, which is given to prevent you from forming an anti-D antibody.”

To explain: Transfusing women of childbearing age with Rh-negative blood avoids a condition called Rh incompatibility, which occurs when a pregnant woman has Rh-negative blood and the baby in her womb has Rh-positive blood. The Rh baby may develop Rh disease, which is a potentially deadly condition that causes the destruction of red blood cells and other problems.

Incompatible Blood Transfusions

 Why is it important for the lab to check your blood for antibodies to other antigens?

“When you get a blood transfusion, you get someone else’s blood. That blood is unique to that other individual. Your body may recognize that it’s foreign and mount a response to the foreign body in your bloodstream. Your blood might become alloimmunized. That happens about 1 percent of the time. So 99 percent of the time people get a transfusion and don’t develop an immune response,” says Dr. Linz.

“The deal is that if you get a blood transfusion and you make an antibody to one of these systems, it’s possible that the antibody is going to react with the next transfused product that you get and you could have a transfusion reaction with the product,” explains Dr. Linz.

In other words, you would have an incompatible blood transfusion.

“If we end up giving an incompatible transfusion, one of the big problems is that your body system destroys the blood that we put in to help you,” says Dr. Linz, “so we haven’t gotten the therapeutic effect that we wanted.”

“That’s why we meticulously cross-match blood,” explains Dr. Linz.

1 thought on “Explaining blood transfusions”

  1. troubledsister

    “Sometimes you may have an illness where you no longer make blood properly.”  this jumped out at me. My brother[age 71] has been receiving a blood transfusion almost every two weeks. He has serious heart disease, diabetes, GERD. He has had every test, scan, etc. and repeated blood tests. Every time his red cell count goes down [8-9] and he feels horrible, he receives another transfusion. He says the doctors just tell him they cannot find any source of blood loss, that meds are controlling  his multiple illnesses as well as possible. Can you help us name and understand this blood condition?

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Explaining blood transfusions