Infectious complications of blood transfusion

Abstract

Some bacterial, parasitic, fungal and viral agents can be transferred by blood transfusion. A number of bacterial infections have been shown to be transmissible by transfusion and some others have the potential for transmission. A serious problem is the occurrence of septic reactions due to the presence of contaminating bacteria in a blood component. Such reactions are often, but not always, dramatic, and among recognized cases, mortality is 25% or greater. The frequency of transfusion-induced sepsis is relatively low among red cell recipients, with a rate that is usually less than one in a million products. The majority of cases of bacterial sepsis is seen among recipients of platelet concentrates. This is generally attributed to the relatively fast growth of bacteria in these components during storage at 20°C. Some studies suggest that one septic event may occur in about every 10,000 transfusions, but other observations show rates that may be substantially higher or lower. Viral agents potentially require cause initially an asymptomatic, viremic phase where the virus can survive in blood during storage. Donor Study and other studies indicate that the risk of receiving a unit of infectious blood is less than 1:500,000 for HIV, 1:100,000 for hepatitis C and 1:70,000 for hepatitis B. In industrialized countries several precautions of safety are employed to ensure the purity of the blood supply. The donor history provides the first major level. Several types of viral testing for the various transfusion transmitted diseases, including HIV 1/2, human T cell lymphoma-leukemia viruses (HTLV I/II), hepatitis C and hepatitis B, provide the second major level of protection. A third major tier of safety currently being developed is pathogen inactivation technology. This technology calls for addition of various additives to blood products to inactivate viruses, bacteria, fungi, protozoa and other transfusion transmitted pathogens. None of the currently available systems is able to inactivate prions such as those that are believed to cause new variant Creutzfeld-Jakob disease (nvCJD). Clinicians must remain alert for infections after transfusion. Avoiding unnecessary and unnecessary transfusions is key to reducing transfusion related infectious complications. In this article, infectious complications of blood and blood components have been reviewed.