A blood transfusion is a medical procedure that involves transferring blood or blood components from one person to another. This is often done to replace lost blood due to surgery, injury, or medical conditions like anemia. The blood used in transfusions is carefully matched to ensure compatibility, reducing the risk of adverse reactions. During a transfusion, the donor's blood is collected and tested for safety before being given to the recipient through an intravenous (IV) line. Blood transfusions can save lives and improve health outcomes, making them a critical part of modern medicine, especially in emergency situations and surgeries.