Storage time of platelet concentrates and all-cause bacteremia in hematologic patients.

Background: Extension of storage time of platelet (PLT) concentrates may result in an increased risk of bacteremia, directly via transfusion of contaminated products or indirectly via transfusion-related immunomodulation. We aimed to quantify the association of storage time of PLT concentrates and all-cause bacteremia in hematologic patients.
Study Design and Methods: We established a cohort of hematologic patients who received a PLT transfusion between 2005 and 2015. Cases were defined as patients with a bacteremia the day after transfusion and matched to as many controls as possible. A conditional logistic regression was performed, stratified by storage medium.
Results: Among 3514 patients receiving 36,032 PLT concentrates stored in plasma, 613 cases of bacteremia were found. The relative risk of all-cause bacteremia the day after transfusion was 0.80 (95% confidence interval [CI], 0.58-1.12) for PLT concentrates stored 3 to 4 days and 0.67 (95% CI, 0.49-0.92) for at least 5 days, compared to no more than 2 days. Among 1527 patients receiving 11,822 PLT concentrates stored in PLT additive solution, 182 cases of bacteremia were found. The relative risk of all-cause bacteremia was 1.14 (95% CI, 0.70-1.84) for PLT concentrates stored for 3 to 4 days and 1.19 (95% CI, 0.70-2.01) for at least 5 days, compared to not more than 2 days.
Conclusion: Storage time of PLT concentrates was not associated with increased occurrence of all-cause bacteremia the day after transfusion. If anything, fewer cases of bacteremia occurred with increasing storage time of PLT concentrates in plasma. These bacteremias are not directly caused by transfusion of a contaminated product and the underlying mechanism warrants further research.
(© 2017 AABB.)