Secondary Bacterial Culture for Platelets Reduces Transfusion Risk and Complies with FDA Draft Guidance for Platelet Safety

Platelets are most susceptible to bacterial contamination due to their storage conditions. In order to decrease the risk of bacterial contamination, in 2016, the FDA issued a draft guidance suggesting additional safety measures beyond a primary bacterial culture for platelets—namely pathogen reduction or secondary bacterial testing.  Pathogen reduction and point-of-release bacterial testing are both costly.  Therefore, the transfusion medicine service at Johns Hopkins implemented a secondary bacterial culture (on day 3 post collection upon arrival at the hospital from the blood supplier a 5 mL aliquot was obtained and cultured aerobically for 3 days at 35°C).  Thirteen months after implementation, 93.5% of platelet products (23,044/24,653) underwent testing, and 8 positive cultures were identified (1 in 2881).  Five of the positive cultures were probable true positives based on repeat testing and were discarded before transfusion.  The remaining three positive cultures were indeterminate.  During the 13 months after secondary bacterial culture implementation, no septic transfusion reactions were recorded.  This strategy may be an effective alternative to comply with the FDA draft guidance.

Reference:

1. Bloch EM, Marshall CE, Boyd JS, Shifflett L, Tobian AAR, Gehrie EA, and PM Ness. Implementation of secondary bacterial culture testing of platelets to mitigate residual risk of septic transfusion reactions. Transfusion 2018