1.
Bacterial culture time to detection in platelet components: An evidence synthesis and estimation of detection failures
Walker BS, Schmidt RL, Moore RA, White SK, Fisher MA, Metcalf RA
Transfusion. 2022
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Editor's Choice
Abstract
BACKGROUND Non-pathogen reduction platelet bacterial risk control strategies in the US FDA guidance include at least one culture. Almost all of these strategies have a culture hold time of ≥12 h. Studies have reported time to detection (TTD) of bacterial cultures inoculated with bacteria from contaminated platelets, but these data and estimates of risk associated with detection failures have not been synthesized. METHODS We performed a literature search to identify studies reporting TTD for samples obtained from spiked platelet components. Using extracted data, regression analysis was used to estimate TTD for culture bottles at different inoculum sizes. Detection failures were defined as events in which contaminated components are transfused to a patient. We then used published data on time of transfusion (ToT) to estimate the risk of detection failures in practice. RESULTS The search identified 1427 studies, of which 16 were included for analysis. TTD data were available for 16 different organisms, including 14 in aerobic cultures and 11 in anaerobic cultures. For inocula of 1 colony forming unit (CFU), the average TTD for aerobic organisms was 19.2 h while it was 24.9 h in anaerobic organisms, but there was substantial overall variation. A hold time of 12 versus 24 h had minimal effect for most organisms. CONCLUSION TTD variation occurs between bacterial species and within a particular species. Under typical inventory management, the relative contribution of culture detection failures is much smaller than the residual risk from sampling failures. Increasing the hold period beyond 12 h has limited value.
PICO Summary
Population
Spiked platelets inoculated into bacterial cultures (16 studies).
Intervention
Systematic review to obtain summary estimates of the time to detection (TTD) for the most common contaminating organisms, and to estimate the risk of detection failures.
Comparison
Outcome
Regression analysis was used to estimate TTD for culture bottles at different inoculum sizes. Detection failures were defined as events in which contaminated components were transfused to a patient. Published data was used on time of transfusion to estimate the risk of detection failures in practice. TTD data were available for 16 different organisms, including 14 in aerobic cultures and 11 in anaerobic cultures. For inocula of 1 colony forming unit, the average TTD for aerobic organisms was 19.2 hours while it was 24.9 hours in anaerobic organisms, but there was substantial overall variation. A hold time of 12 vs. 24 hours had minimal effect for most organisms.
2.
The epidemiology of transfusion-related acute lung injury: A scoping review and analysis
White SK, Schmidt RL, Walker BS, Metcalf RA
Transfusion. 2022
Abstract
BACKGROUND The purpose of this scoping review was to identify available sources of evidence on the epidemiology of transfusion-related acute lung injury (TRALI) and whether meta-analysis on the incidence of TRALI is feasible. TRALI is a serious complication and the second leading cause of death related to blood transfusion. Estimates of the incidence of TRALI would provide a useful benchmark for research to reduce TRALI. STUDY DESIGN AND METHODS We searched the Medline, EMBASE, and PubMed databases for publications related to the incidence of TRALI and hemovigilance. We included all studies irrespective of language or country. Both full-text articles and conference abstracts were included. Participants of the studies must all have received a blood transfusion. Reviews and case studies were excluded. RESULTS We identified 427 articles or abstracts to include for review. More than half were abstracts, and the majority were published after 2010. Reported TRALI definitions varied, but only 27.2% of studies reported any definition for TRALI. TRALI rates were reported using different denominators, such as per blood unit (54.1%), patient (34.4%), and transfusion episode (14.8%). Study populations and contexts were mostly general (75.6% and 80.3%, respectively). There was also variation in study design with most being observational (90.6%) and only 13.1% of all studies used modern donor restriction policies. DISCUSSION There was substantial variation in reporting in studies on TRALI incidence. Meta-analysis of TRALI rates may be feasible in specific circumstances where reporting is clear. Future studies should clearly report key items, such as a TRALI definition.
3.
Residual bacterial detection rates after primary culture as determined by secondary culture and rapid testing in platelet components: A systematic review and meta-analysis
Walker BS, White SK, Schmidt RL, Metcalf RA
Transfusion. 2020
Abstract
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(SC) ) was 0.93 (95% CI, 0.24-0.6) per 1000 components, while residual detection rate using rapid testing (DR(RT) ) 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.
4.
Bacterial contamination rate of platelet components by primary culture: a systematic review and meta-analysis
White SK, Schmidt RL, Walker BS, Metcalf RA
Transfusion. 2020;60(5):986-996
Abstract
BACKGROUND Platelets have the highest bacterial contamination risk of all blood components, and septic transfusion reactions remain a problem. A good estimate of contamination rates could provide information about residual risk and inform optimal testing strategies. We performed a systematic review and meta-analysis of platelet contamination rates by primary culture. STUDY DESIGN AND METHODS A literature search in December 2019 identified articles on platelet contamination rates using primary culture. We used meta-analysis to estimate the overall rate of contamination and meta-regression to identify heterogeneity. We studied the following sources of heterogeneity: collection method, sample volume, positivity criteria, and study date. Contamination rate estimates were obtained for apheresis (AP), platelet rich plasma (PRP), and buffy coat (BC) collection methods. RESULTS The search identified 6102 studies, and 22 were included for meta-analysis. Among these 22 studies, there were 21 AP cohorts (4,072,022 components), 4 PRP cohorts (138,869 components), and 15 BC cohorts (1,474,679 components). The overall mean contamination rate per 1000 components was 0.51 (95% CI: 0.38-0.67) including AP (0.23, 95% CI: 0.18-0.28), PRP, (0.38, 95% CI: 0.15-0.70), and BC (1.12, 95% CI: 0.51-1.96). There was considerable variability within each collection method. Sample volume, positivity criteria, and publication year were significant sources of heterogeneity. CONCLUSION The bacterial contamination rate of platelets by primary culture is 1 in 1961. AP and PRP components showed a lower contamination rate than BC components. There is clinically significant between-study variability for each method. Larger sample volumes increased sensitivity, and bacterial contamination rates have decreased over time.
5.
The incremental benefit of anaerobic culture for controlling bacterial risk in platelets: a systematic review and meta-analysis
Corean J, White SK, Schmidt RL, Walker BS, Fisher MA, Metcalf RA
Vox sanguinis. 2020
Abstract
BACKGROUND AND OBJECTIVES Septic transfusion reactions are a principal cause of transfusion-related mortality. The frequency of detectable bacterial contamination is greater in platelets compared to other blood components because platelets are stored at room temperature. Most strategies outlined in the September 2019 FDA guidance require both aerobic culture (AC) and anaerobic culture (AnC) testing. We performed a systematic review and meta-analysis in an effort to provide the best available estimate of the effectiveness of AnC. MATERIALS AND METHODS Our analysis was performed according to published guidelines. Broad and context-specific meta-analyses of bacterial detection rates in platelets by AnC were performed to assess the practical effectiveness of AnC as a risk control measure. RESULTS Seven studies with a total of 1 767 014 tested platelet components were included for analysis. With exclusion of positives due to Cutibacterium/Propionibacterium species and redundancy due to AC results, AnC detected 0·06 contamination events per thousand (EPT) components tested, twofold lower than the AC (0·12 EPT). CONCLUSION Excluding Cutibacterium/Propionibacterium species, AnC detects occasional bacterial contamination events that are not detected by AC (~1 in 17 000 platelet components).