Bacterial contamination of platelet components: potential solutions to prevent transfusion-related sepsis

Bacterial contamination of platelet components (PC) is the most prevalent risk for transfusion-transmitted infection. Based on the recent studies with optimal culture methods of expired PC, the prevalence of bacterial contamination is estimated to occur in approximately one in 750 to one in 1000 PC. Only within the last few years have the magnitude of the risks and the range of clinical outcomes associated with bacterial contamination been extensively characterized. Despite increased recognition of bacterial contamination of PC, transfusion-related sepsis is infrequently reported. This has largely been attributed to passive reporting systems, and low levels of clinical awareness for transfusion-related sepsis by primary care physicians. The risk for transfusion of contaminated PC has generally been characterized per component. Importantly, because patients require repeated transfusions of PC during a period of transfusion-dependent thrombocytopenia, it is appropriate to express the risk to receive a contaminated PC on a patient exposure basis. Assuming that the average hematology oncology patient may receive seven PC during a 28-day period of support, the risk of exposure to a contaminated PC is in the range of one in 150 per patient. This level of risk would not be acceptable for other intravenous medications. With increased appreciation of the risk of bacterial contamination, methods were developed to limit the risk of transfusion-transmitted bacteremia. This article focuses on those interventions that have been implemented in routine practice. The most important methods employed to mitigate the risk are improved skin disinfection, initial blood draw diversion, bacterial detection and pathogen inactivation/reduction. These technologies are now undergoing increased use in the clinical practice of transfusion medicine. With increased use, additional data are being generated to more fully characterize the effects of these interventions. Improved disinfection, blood diversion and bacterial detection have decreased, but not resolved the risk of bacterial contamination. Pathogen inactivation/reduction offers the potential for a further substantial decrease of the risk for transfusion of PC contaminated with bacteria.