Blood Transfusion and Donation

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Types of transfusions

Red blood cell transfusions

Red blood cell basics

Red blood cells (RBCs) give blood its color. Their job is to carry oxygen from the lungs through the bloodstream to every part of the body. A substance in red blood cells called hemoglobin (HE-muh-glo-bin) does this. Then, the red cells bring carbon dioxide (CO2) back to the lungs, where it’s removed from the body when we exhale.

Red blood cells (and all other blood cells) are normally made in the bone marrow, the soft inner part of certain bones. The production of RBCs is controlled by the kidneys. When the kidneys sense that there aren’t enough RBCs in the blood, they release a hormone called erythropoietin (eh-rith-ro-POY-uh-tin) that causes the bone marrow to make more.

When red blood cell transfusions are used


People who have low numbers of red blood cells (RBCs) are said to have anemia (uh-nee-me-uh) or they are anemic (uh-nee-mik). People who have anemia may need RBC transfusions because they don’t have enough RBCs to carry oxygen to all of the cells in the body. (Low iron or B12 levels are less common causes of anemia in cancer patients.)

A normal hemoglobin level is 12 to 18 g/dL; a red blood cell transfusion may be suggested if it drops below 8 g/dL. Whether you need a transfusion for anemia depends on many factors, such as how long it took for the anemia to develop and how well your body is able to cope with it. Anemia due to a sudden loss of blood will probably need to be corrected right away. Anemia that develops slowly is less likely to cause problems, because the body has time to adjust to it to some extent. If your hemoglobin level is lower than normal but you’re not dizzy, pale, or short of breath, you may not need a transfusion.

Patients who have certain heart or lung diseases may be more affected by anemia and may need transfusions even if their hemoglobin level is not very low. Other conditions that increase the need for oxygen may also require transfusions.

There are drugs that can treat anemia instead of a transfusion in some patients, but they carry different risks, work slowly, and cost a lot. For more information about anemia and how it’s treated, see our document called Anemia in People With Cancer.


Transfusions may be given during or after surgery to make up for blood loss. Some studies have suggested patients with certain cancers, like colorectal, prostate, lung (small cell or non-small cell), and breast cancer, have worse outcomes if transfusions are given before or during surgery. The reasons for this are not clear, but transfused blood may affect the immune system in ways that may cause problems later. The information can be hard to make sense of because many of the studies only looked at people who had and hadn’t been transfused, so the groups may have started with major differences. For instance, patients who need transfusions are often sicker to start with, and they may be treated in different ways afterward. These studies need to be confirmed by careful research.

Keep in mind, too, that while it might be possible to reduce the number of transfusions, totally avoiding them can cause serious risks or even death in some people. The decision to transfuse should be made in the context of other factors as well, such as the patient’s symptoms and overall health.

Plasma transfusions

Plasma basics

Plasma is the clear, pale-yellow liquid part of blood. It contains proteins (called clotting factors) that help make blood clot. This is important when the body is injured because clots are needed to help seal blood vessels and stop bleeding. Plasma also contains other proteins, such as antibodies (AN-tih-bah-dees), which help fight infection.

Once plasma is separated from the red blood cells, it can be frozen and kept for up to a year. Once thawed, it’s called fresh frozen plasma.

Plasma can be donated in a process called apheresis (a-fur-REE-sis), or sometimes called plasmapheresis (plaz-muh-fur-REE-sis). The donor is hooked up to a machine that removes blood, separates the plasma, and puts it into a special container. The machine returns the red cells and other parts of the blood to the donor’s bloodstream.

When plasma transfusions are used

Plasma is commonly given to patients who are bleeding because their blood is not clotting the way it should. Cancer patients might also be given fresh frozen plasma if they have a problem called DIC (disseminated intravascular coagulation). In this rare condition, all of the clotting factors in the body are used up or broken down. Signs and symptoms (such as excessive bleeding and bruising) and blood tests help the doctor identify DIC.

Platelet transfusions

Platelet basics

Platelets are fragments of cells in blood and are another important part of the clotting process. They work with the clotting factors in plasma to help prevent bleeding. Platelets come from special cells in the bone marrow called megakaryocytes. (meg-uh-KAIR-ee-oh-sites)

Platelets are usually found in the plasma, and like red blood cells, they can be separated from it. A unit of whole blood has only a small volume of platelets. It takes platelets from several units of whole blood (from different donors) to help keep a person from bleeding. A unit of platelets is defined as the amount that can be separated from a unit of whole blood.

Unlike red blood cells, platelets do not have a blood type (see “Blood types” in the section called “How blood transfusions are done”), so patients can usually get platelets from any qualified donor. For platelet transfusions, 6 to 10 units from different donors (called random donor platelets) are combined and given to adult patients at one time (they are called pooled platelets).

Platelets can also be collected by apheresis (a-fur-REE-sis). This is sometimes called plateletpheresis (plate-let-fur-REE-sis). In this procedure, the donor is hooked up to a machine that removes blood, and keeps just the platelets. The rest of the blood cells and plasma are returned to the donor. Apheresis can collect enough platelets so that they don’t have to be combined with platelets from other donors. Platelets collected in this way are called single donor platelets. (You can find more information about this is in the section called “Donating blood.”)

When platelet transfusions are used

Cancer patients may need platelet transfusions if their bone marrow is not making enough. This happens when platelet-producing bone marrow cells are damaged by chemo or radiation therapy or when they are crowded out of the bone marrow by cancer cells.

A normal platelet count is about 150,000 to 400,000 platelets per cubic millimeter (mm3), depending on the lab. When platelet counts drop below a certain level (often 20,000/mm3), a patient is at risk for dangerous bleeding. Doctors may think about giving a platelet transfusion when the platelet count drops to this level or even at higher levels if a patient needs surgery or may be at risk of bleeding. If there are no signs of bleeding, a platelet transfusion may not be needed even if the platelet count is low.

Currently there is one drug, called interleukin-11 (oprelvekin or Neumega®), that doctors can give to help raise a person’s platelet counts without transfusions. Like other medicines to help blood counts, it takes time for this drug to raise the platelet counts, anywhere from 10 to 21 days.

Cryoprecipitate transfusions

Cryoprecipitate basics

Cryoprecipitate (cry-o-pre-SIP-ih-tate) is the name given to the small fraction of plasma that separates out (precipitates) when plasma is frozen and then thawed in the refrigerator. It has several of the clotting factors found in plasma, but they are concentrated in a smaller amount of liquid. A unit of whole blood has only a small amount of cryoprecipitate, so about 8 to 10 units of cryoprecipitate (from different donors) are pooled together for one transfusion.

When cryoprecipitate transfusions are used

Cryoprecipitate may be given to replace several blood clotting factors such as:

  • Factor VIII (missing in patients with hemophilia A)
  • Von Willebrand factor (needed to help platelets work)
  • Fibrinogen (a substance that can solidify into a clot)

Unless they are bleeding, people with cancer rarely need cryoprecipitate.

White blood cell (granulocyte) transfusions

White blood cell basics

Chemotherapy can damage cells in the bone marrow, and patients getting chemo often have low white blood cell (WBC) counts (the normal range is 4,000 to 10,000 per cubic millimeter [mm3]) .

White blood cells, especially the type called neutrophils (new-trow-fills), are very important in fighting infections. When patients have low WBC counts, doctors carefully watch the number of neutrophils or the absolute neutrophil count (ANC). People with neutropenia ([new-trow-PEEN-ee-uh] an ANC below 1,000/mm3) are at risk for serious infections, even more so if the count stays low for more than a week.

When white blood cell transfusions are used

At one time, white blood cell transfusions were commonly given to cancer patients who could not make enough of these cells on their own or whose WBCs had been destroyed by disease or medicines. But for many reasons, such transfusions now are given rarely. For instance, it’s not clear how well the transfusions help reduce the risk of serious infections. And WBC transfusions can also cause a fever known as a febrile transfusion reaction. They can sometimes transmit infectious diseases, such as cytomegalovirus (CMV), which can be dangerous for people who have weak immune systems.

Instead of transfusing WBCs, doctors now commonly use drugs called colony-stimulating factors or growth factors to help the body make its own neutrophils:

  • Granulocyte colony-stimulating factor (G-CSF), such as filgrastim (Neupogen®) and pegfilgrastim (Neulasta®)
  • Granulocyte-macrophage colony-stimulating factor (GM-CSF), such as sargramostim (Leukine®)

Last Medical Review: 10/07/2013
Last Revised: 10/07/2013