Background: The danger of bacteremia due to contaminated platelets is not well known. There are also no established guidelines for the management of febrile reactions after platelet transfusion.
Study design and methods: To determine the risk of symptomatic bacteremia after platelet transfusion, 3584 platelet transfusions given to 161 patients after bone marrow transplantation were prospectively studied. Platelet bags were routinely refrigerated for 24 hours after transfusion. Septic work-up was initiated for a temperature rise of more than 2 degrees C above the pretransfusion value within 24 hours of platelet transfusion or a temperature rise of more than 1 degree C that was associated with chills and rigor. Diagnosis of bacteremia after platelet transfusion was made only when the pairs of isolates from the blood and the platelet bags were identical with respect to their biochemical profile, antibiotic sensitivity, serotyping, or ribotyping.
Results: Thirty-seven febrile reactions, as defined above, occurred. Bacteremia subsequent to platelet transfusion was diagnosed in 10 cases. There was a 27-percent chance (95% CI, 15-43%) that these febrile reactions represented bacteremia that resulted from platelet transfusion. For a subgroup of 19 patients with a temperature rise of more than 2 degrees C, the risk of bacteremia was 42 percent (95% CI, 23-64%). Septic shock occurred in 4 of the 10 bacteremic patients. A rapid diagnosis was possible because the involved bacteria were demonstrated by direct Gram stain of the samples taken from the platelet bags of all 10 patients.
Conclusion: Significant febrile reactions after platelet transfusion are highly likely to be indicative of bacteremia. Routine retention of platelet bags for subsequent microbiologic study was useful in the investigation of these febrile reactions. Empiric antibiotic therapy is indicated.