Residual bacterial detection rates after primary culture as determined by secondary culture and rapid testing in platelet components: A systematic review and meta-analysis.

Background: Primary culture alone was a bacterial risk control strategy intended to facilitate interdiction of contaminated platelets (PLTs). A September 2019 FDA guidance includes secondary testing options to enhance safety. Our objective was to use meta-analysis to determine residual contamination risk after primary culture using secondary culture and rapid testing.

Study Design And Methods: A December 2019 literature search identified articles on PLT bacterial detection rates using primary culture and a secondary testing method. We used meta-analysis to estimate secondary testing detection rates after a negative primary culture. We evaluated collection method, sample volume, sample time, and study date as potential sources of heterogeneity.

Results: The search identified 6102 articles; 16 were included for meta-analysis. Of these, 12 used culture and five used rapid testing as a secondary testing method. Meta-analysis was based on a total of 103 968 components tested by secondary culture and 114 697 by rapid testing. The residual detection rate using secondary culture (DR ) was 0.93 (95% CI, 0.24-0.6) per 1000 components, while residual detection rate using rapid testing (DR ) was 0.09 (95% CI, 0.01-0.25) per 1000 components. Primary culture detection rate was the only statistically significant source of heterogeneity.

Conclusion: We evaluated bacterial detection rates after primary culture using rapid testing and secondary culture. These results provide a lower and upper bound on real-world residual clinical risk because these methods are designed to detect high-level exposures or any level of exposure, respectively. Rapid testing may miss some harmful exposures and secondary culture may identify some clinically insignificant exposures.