SUMMARY OF SAFETY AND EFFECTIVENESS
Seven Day Platelet Storage Using Platelets Collected with the COBE Spectraä Apheresis System and the Trimaâ Automated Blood Component Collection Systems and Release Tested with the BacT/ALERTâ Microbial Detection Systems
Previously published data on platelet function for single donor platelets (SDP) in the ELP bag demonstrated maintenance of in vitro properties and effective in vivo recovery in an autologous transfusion model using healthy volunteers. SDP has previously been demonstrated to present an incremental safety advantage over platelets from whole blood, and the use of SDP is suggested by AABB as one prevention strategy to reduce the risk of transfusion associated bacterial septic reactions. The addition of 100% bacterial screening with the BacT/ALERT culture system adds another margin of safety for 7-day stored SDP.
Methods used for the collection of SDP aliquots for testing, testing practices and results were obtained from major blood suppliers in the United States. The data presented represents bacterial test results using the BacT/ALERT from 405,089 SDP collections performed since implementation of 100% bacterial testing for quality control purposes pursuant to AABB Standard 188.8.131.52. covering the period of approximately March 1, 2004 through approximately October 31, 2004.
Overall, there were a total of 405,089 SDP collections tested with 72 confirmed positives (178 per million, 95%CI 139/M - 224/M). Assuming all indeterminate events were also true positives, there were a total of 118 positive events for a rate of 291/M (95% CI 241/M - 349/M). There were a total of 203 false positives either attributed to equipment failure or confirmatory testing was negative on the SDP. No transfusion associated septic events were associated with platelets transfused prior to the detection of a positive culture in the test instrument. Fast growing, gram negative organisms were typically detected within 12 hours following bottle inoculation. One organization used both aerobic and anaerobic bottles, and detected four true positives. On two occassions organisms (Enterbacter aerogenes, staphylococcus aureus) were detected in both the aerobic and anaerobic bottles. On two other occasions, coagulase negative staphylococcus was detected in the anaerobic bottles only. In addition, there were 8 instances of proprionibacterium acnes detected in only the anaerobic bottles at or beyond three days of bottle incubation; no reactions were associated with the transfusion of the products that had positive p. acnes cultures.
All participating organizations had a minimum hold time prior to SDP sampling of 24 hours, all used aerobic culture bottles, one center used an additional anaerobic bottle for their 6600 collections tested, all obtained one sample per collection taken from a well mixed combined SDP prior to division into multiple products (i.e. splitting), and all used a targeted 4mL or 4-5 mL platelet inoculum per bottle. All organizations practice release negative-to-date after quarantine of SDP following bottle inoculation, with quarantine times of zero hours for 2 organizations, 12 hours for 1, and 24 for the remaining 2. Laminar flow hoods were not used for product sampling. Two organizations used laminar flow hoods for bottle inoculation.
A standardized protocol for sampling, handling, quarantine and Release Testing of SDP collected and stored using Gambro systems is presented. Blood centers complying with this method may extend their storage time for SDP prior to transfusion up to 7 days. Blood establishments, both licensed and registered, planning on using the Gambro 7-day ELP storage system should contact CBER for the appropriate regulatory pathway and submission requirements prior to their implementation of 7-day storage.
Because of the low incidence of the contaminating bacteria in SDP, a post-marketing surveillance study targeted to estimate the performance of the bioMérieux BacT/ALERT Microbial System when used as a Release Test with the Gambro SDP will be conducted.
The Gambro ELP Platelet Storage System may store leukocyte-reduced apheresis Platelets collected with the COBE Spectra Apheresis System and Gambro Trima Automated Blood Component Collection System for up to and including 7 days when coupled with a 100% release test screening for bacterial contamination using BacT/ALERT Microbial detection Systems as described in the Gambro ELP platelet Storage System Instructions for Use (IFU).
The effective storage range for platelets in plasma kept in the ELP bag under standard conditions is: 100-400 mL/bag, 1.0-2.1 x 106 platelets/µL, Maximum 5.1 x 1011 platelets per bag.