Blood and blood components are key elements in treating patients. But blood can contain potentially harmful elements such as bacteria, viruses and parasites, which can be transmitted to the patient. A blood transfusion may also trigger allergic reactions or cause transfusion-associated graft versus host disease (TA-GVHD) in patients. Thorough testing can reduce some of the known infectious risks, but these tests do not always detect emerging or re-emerging diseases.
The transfusion of blood components may trigger an allergic reaction ranging from complaints of hives and itching to wheezing, fever or even anaphylaxis and anaphylactic shock, which can be fatal if not immediately treated.