FDA guidance on bacterial contamination risk control strategies to enhance the safety and availability of platelets: advantages and limitations

Bacterial contamination of platelets was first addressed by primary culture, introduced in US in 2004, which ameliorated but did not solve the problem. Guidance to further decrease bacterial contamination were published by the US Food and Drug Administration in September 2019; recommended implementation is by October 2021. These include three single-step strategies: (I) culture at ≥36 h of ≥16 mL (≥8 mL aerobic, ≥8 mL anaerobic) per split apheresis unit or whole-blood derived pool; 5 day outdate; (II) culture at ≥48 h of ≥16 mL (≥8 mL aerobic, ≥8 mL anaerobic) per split apheresis unit; 7 day outdate; (III) pathogen reduction of apheresis units performed within 24 h of collection (5-day outdate). Several two-step strategies are available: First step has two options: (I) culture ≥36 h of ≥16 mL as in single-step option 1 (5 day outdate); (II) culture at ≥24 h after collection of ≥16 mL (≥8 mL aerobic, ≥8 mL anaerobic) per apheresis collection or split unit, or whole-blood derived pool (3 day outdate). The second step has three options to extend these outdates: (I) secondary culture of each unit of ≥8 mL (aerobic) on ≥ day 3 (extends outdate to 5 days); (II) secondary culture of each unit of ≥16 mL as in step 1 on ≥ day 4 (extends outdate to 7 days); (III) rapid testing of each unit within 24 hours of transfusion on ≥ day 3 (extends outdate to 7 days). This review addresses advantages and limitations of these strategies based on evidence of their efficacy.