What Is a Homologous Blood Transfusion?

A homologous blood transfusion is an intravenous infusion of blood that has been donated by another person. This contrasts to autologous blood transfusions, where a person receives his own previously donated blood. Most individuals get donor blood, but a few people who are concerned about the possible complications of homologous blood prefer autologous transfusions, if they have time to prearrange donating. As provided blood is screened and carefully matched, homologous transfusions are considered very safe. Nevertheless, there are a few rarely occurring reactions or risks that accompany receiving them.

Any form of blood transfusion is given in roughly the same way. A bag containing whole blood or a blood product like red blood cells is connected to a small catheter, which is typically inserted in a vein in the arm or leg. Blood may be transfused at different rates, depending on how quickly it is needed. Doctors determine, based on that need, whether more than one transfusion is necessary.

Patients receive a homologous blood transfusion for a variety of reasons, and these may be further divided into certain types. Some individuals get whole blood, but others receive platelets, red blood cells, or plasma, depending on medical need. The most common reasons for getting a transfusion include surgery, injury, or diseases that affect blood cell supply.

It's still important that the homologous blood transfusion be matched between a donor and the person receiving it. Humans have four blood types — A, B, AB, and O — and each type also has an RH factor, described as positive or negative. People with positive blood can receive negative or positive donations, while those with negative blood can only get other negative types. O- is the most desired because all blood types can receive it, and AB+ is the easiest blood to match, since people with this type may receive any other kind. If there is time to prepare, as for a surgery or a planned transfusion, doctors will often order an exact match, but in emergencies, medical personnel know they can give certain kinds of blood to various patients without creating reactions in the majority of individuals.

The homologous blood transfusion can also be separated into two types. People can get blood product from an anonymous donor, or family and friends who have matching blood types may donate. Many people prefer to use family and friend donations, but this isn’t always safer. In some instances, screening hasn’t been as rigorous, and known donors have passed dangerous illnesses to friends or relatives receiving their blood.

This is part of the worry that drives people to consider autologous blood transfusions. By only receiving blood from one's self, the likelihood of negative reactions or development of disease is greatly reduced. Some of the complications that very occasionally arise from a homologous blood transfusion include reaction to the transfusion, transmission of viruses like HIV and hepatitis C, or extreme kidney damage. For almost all people, these risks are very low, and the most common adverse reactions, like too much iron in the blood or a slight fever, can be quickly treated.