Bacterial contamination of platelet concentrates: incidence, significance, and prevention.

Severe transfusion reactions associated with bacteria and/or their products, during or following a blood transfusion, were one of the earliest recognized complications of allogeneic blood transfusions. Bacterial contamination of blood products has thus been a problem for many decades and at present is likely the most common microbiological cause of transfusion-associated morbidity and mortality. Transfusion-associated sepsis due to contaminated platelet concentrates appears to be much more common than that due to contaminated red blood cells. The overall incidence of contaminated cellular blood products is approximately 1 in 3,000. However, transfusion to a recipient of a contaminated platelet unit may not necessarily be associated with clinically apparent morbidity, because the majority of contaminated platelet units contain relatively few organisms. In a minority of instances, contaminated units contain large numbers of potentially virulent bacteria, as well as endotoxins, and their transfusion is often associated with significant recipient morbidity and mortality. The incidence of severe septic episodes has not been clearly established, but is probably of the order of 1 per 50,000 platelet units transfused. With heightened awareness in recent years of the possibility that platelet transfusion-associated septic episodes can occur, a variety of measures have been proposed, and in some cases implemented, to try to prevent and control this transfusion risk. Copyright 2001 by W.B. Saunders Company.