Overview of blood transfusion

[PussyCat]

A blood transfusion is the transfer of blood or a blood component from one healthy person (a donor) to a sick person (a recipient). Transfusions are given to increase the bloods ability to carry oxygen, restore the amount of blood in the body (blood volume), and correct clotting problems.
In the United States, about 21 million blood transfusions are given every year. Typical transfusion recipients include

People who have been injured
People undergoing surgery
People receiving treatment for cancers (such as leukemia)
People receiving treatment for other diseases (such as the blood diseases sickle cell disease and thalassemia)

In the United States, the Food and Drug Administration (FDA) strictly regulates the collection, transportation, and storage of blood and its components. These regulations were developed to protect both the donor and the recipient. Additional standards are upheld by many state and local health authorities, as well as by organizations such as the American Red Cross (see Eligibility Requirements) and the AABB (formerly, the American Association of Blood Banks). Because of these regulations, giving blood and receiving blood are very safe.
However, transfusions still pose risks for the recipient, such as allergic reactions, fever and chills, excess blood volume, and bacterial and viral infections. Even though the chance of contracting AIDS, hepatitis, or other infections from transfusions is remote, doctors are well aware of these risks and order transfusions only when there is no alternative. Before ordering a transfusion (except in an emergency), doctors explain the risks of transfusion to people and ask them to sign a document affirming that they understand the risks and giving their consent for transfusion (called informed consent).
Rarely, some donors may also develop side effects following donation, including giddiness, low blood pressure, nausea, and tingling/numbness at the site of needle insertion for the blood draw.