Where Do Blood Components Come From?
Blood components are obtained from blood from volunteer blood donors. Blood donation programs allow blood to be donated by:
- A patient for themselves
- Anonymous donors
- In some cases, by someone specified by the patient
Blood may be processed into any of these blood components:
Whole blood contains red blood cells and plasma. Whole blood is often used for open heart surgery. It may also be used for exchange transfusions (complete replacement of a baby's blood) in newborns with hemolytic disease of the newborn. It is not common for this product to be used for other reasons.
Packed Red Blood Cells
Red blood cells carry oxygen to the tissues. Packed red blood cells have had most of the plasma removed from the whole blood. Packed cells are most often given into a vein over two to four hours. This is given to replace the red cells lost through bleeding, hemolysis (destruction of the red blood cells), or when the bone marrow produces fewer red cells. The decreased production of cells may be due to bone marrow failure, cancer involving the marrow, the effect of chemotherapy drugs used to treat a cancer, or anemia due to prematurity.
Fresh Frozen Plasma
Contains clotting factors. Fresh frozen plasma is plasma which was frozen and stored shortly after it was obtained from the blood donor. Fresh frozen plasma contains many clotting factors. It is often used alone or with cryoprecipitate to replace the low levels of clotting factors. It is most often given into a vein over one to two hours.
Blood cell fragments which help blood clot. Platelets are the cell fragments which prevent or stop bleeding or bruising by plugging the hole in the blood vessel. Platelets are most often given into a vein over a few minutes to an hour. If a patient's bone marrow is not making platelets, then platelet transfusions are most often needed one time or two times a week (or even more often). Platelets may also be given when a patient's platelets are not working the right way due to medicines, illness, or mechanical damage (such as from an artificial heart valve).
Cryoprecipitate is the part of the blood which contains only certain clotting factors such as factor VIII (deficient in hemophilia A), von Willebrand factor and fibrinogen. Cryoprecipitate is now most often given only as a source of fibrinogen (needed for forming a clot). Some patients with certain types of hemophilia or patients who lack fibrinogen may receive cryoprecipitate to treat their clotting defect. Also, very ill patients may develop an abnormal clotting condition known as DIC (disseminated intravascular coagulation). This can cause a decrease in the body's clotting factors and result in severe bleeding. Cryoprecipitate, along with fresh frozen plasma (see above), may be given to help replace the clotting factors that are low. Cryoprecipitate is most often given over just a few minutes to an hour into a vein.
Cells which help fight infections. Granulocytes are also called neutrophils. They are cells which help fight off bacterial or fungal infections. Granulocytes are sometimes given to help fight off severe infections in patients who have very low numbers of granulocytes in the blood and have not responded to medicine. Most often granulocytes are given daily for five days or until the patient's granulocyte count returns to a level which allows the patient to fight the infection on their own. Granulocytes are most often infused into a vein over one to two hours.
What Are Possible Risks of Use of a Blood Component?
Sometimes there are adverse reactions that occur with the use of a blood component. Most of these reactions are not common and can most often be easily managed. If an adverse reaction occurs, other methods to solve the problem may be used.
- Immune mediated adverse reactions can occur if a patient's immune system reacts to the blood component. It can also happen if the immune cells in the blood component react to the patient's cells or fluids. These reactions are not common.
They may include:
- Allergic reactions
- Anaphylactic reaction
- Development of red blood cell or platelet antibodies which shorten the lifespan of these cells in the bloodstream
- Transfusion-related damage to the lung tissue (TRALI)
- Delayed destruction of red blood cells
- Graft versus host disease (GVHD)
There are also non-immune mediated adverse reactions that can occur. Most of them are rare. These may include:
- Bleeding problems
- Fluid overload
- Reaction from extra potassium in the blood component
- Tingling of the hands and lips caused by lowered blood calcium level
- An overload of iron in the body tissues (which can occur in patients who receive more than 100 units of red blood cell transfusions)
An infection could occur from the use of a blood component that contains bacteria, a virus (like cytomegalovirus, hepatitis B and C, or HIV) or a parasite. Infections from transfusions are rare since screening blood donors and testing and filtering blood has made the blood supply in the United States the safest that it has ever been. The risk of contracting hepatitis B can be further reduced with a vaccine.
Learn more about these risks by speaking with your healthcare team, by reading details of these adverse reactions and by visiting recommended websites.
What Are Symptoms of a Possible Problem of Use of a Blood Component?
Symptoms to watch for include:
- Fever over 100.6°F (38°C) taken by mouth, blood pressure changes
- Chills, headache, belly aches, throwing up, loose stools or back pain
- Dark-colored urine, hives, itching, wheezing or shortness of breath or problems breathing
- Swelling of feet or ankles, or a cough that was not there before the transfusion
- Delayed reactions. In rare cases, a delayed reaction can happen three to 10 days after a transfusion of red blood cells. Call your child's doctor if your child gets a fever or becomes pale or jaundiced (yellow color in skin and whites of eyes) three to 10 days after a blood transfusion.
If your child has symptoms after receiving a blood product, call your nurse or doctor right away.
What Are Alternatives to Blood Components?
Sometimes there are other choices. Your healthcare team can talk to you about which ones may be used, based on your child's condition. These can include:
- Drugs which can stimulate the bone marrow to make more red blood cells (erythropoietin), white blood cells (granulocyte-colony stimulating factor) and platelets (interleukin-11). Newer agents are being developed.
- Bleeding problems can be treated by giving specific clotting factors (such as coagulation factor VIII or IX concentrates), or by giving drugs which decrease the risk of bleeding in the mouth and throat (Amicar) or increase the level of certain coagulation factors (DDAVP). If the bleeding is caused by too much heparin in the body, this can be reversed by protamine sulfate.
- Some patients who have surgery can have their own blood stored before the surgery. After the surgery, they get their own blood back (an autologous unit). Other patients may have their blood which is lost during surgery given back to them (intraoperative salvage procedure).
- You may also ask a specific donor to give blood for the transfusion, if the donor is compatible and the blood is free of infectious agents. Experience has shown that these directed donor units are not any safer than blood from a normal volunteer blood donor. Some patients can tolerate a low hemoglobin level for a few days after surgery and build back their own blood supply by taking extra iron.
- Note that directed donor blood is rarely used in the newborn intensive care setting because of the time needed to screen and process this blood.
Some patients, for religious reasons, try to avoid blood product transfusions. The above alternatives are available to them. In the future, a blood substitute may become an option for such patients.
What Are Additional Resources to Learn More about Blood Components?
For more information about blood components, speak with your child's doctor. You can also find information on these websites: