Survey of methods used to detect bacterial contamination of platelet products in the United States in 2011

Abstract

Background: Testing of platelets (PLTs) for bacterial contamination is required by the AABB Standards but is not fully standardized. On January 31, 2011, a new AABB Standard, 5.1.5.1.1, specified that bacterial detection methods for PLT components shall use assays either approved by the Food and Drug Administration (FDA) or validated to provide sensitivity equivalent to these FDA-approved methods.

Methods: An Internet-based survey of AABB member institutions was conducted from May to June 2012, to document current practices used in 2011 for bacterial detection in different PLT products and to assess the impact of the new standard.

Results: Of 1053 AABB member institutions surveyed, 40 of 99 blood centers (40.4%) and 184 of 954 hospital blood banks or transfusion services (19.3%) responded. Sixty-four respondents manufactured PLTs. Apheresis PLTs (APs) were predominantly screened with the BacT/ALERT system (89.5%); the majority (95.2%) were cultured with at least 8 mL of product. There was substantial variation in the minimum incubation time of cultures before release of PLTs (range, 0 to >24 hr). Recalls of released AP for possible bacterial contamination were largely successful (67.3%); successful interdiction before transfusion was associated with incubation for more than 12 hours before release (p < 0.01). After Standard 5.1.5.1.1 took effect, there was a decrease in production of whole blood-derived PLT concentrates (WBPCs). Point-of-issue ("rapid") immunoassays were used to screen a substantial proportion of WBPC PLTs, but were rarely used as secondary tests for previously cultured APs.

Conclusion: The survey identified variability in culture methods and release times with AP, while use of WBPC decreased after AABB Standard 5.1.5.1.1 became effective.