What’s the difference between autologous, homologous (allogenic), and heterologous blood transfusions?

Autologous blood transfusion is the collection and re-infusion of the patient’s own blood or blood components. Homologous, or more correctly allogenic, blood transfusions involves someone collecting and infusing the blood of a compatible donor into him/herself. Heterologous blood transfusions are those that involve someone infusing blood and its components from a different species. Withdrawal, storage and preservation, and re-infusion of blood products are carefully regulated in the health industry because infusion of infectious, old, or incorrectly matched blood could result in hospitalization and possibly death.