Bacterial contamination of platelet concentrates produced in New Zealand.

AIMS

To identify the rate of bacterial contamination of platelet concentrates in New Zealand and compare with other countries who use the BacT/ALERT screening system. To report on septic transfusion reactions associated with platelet transfusion in New Zealand.

METHODS

Six mL of platelet concentrate is inoculated into a BacT/ALERT BPA (aerobic culture) bottle on Day 2 post-collection. Bottles that are flagged as positive are sent to the microbiology laboratory, with the associated unit, for confirmatory testing. Platelet units that have expired are sampled again. Results from the four blood processing sites in New Zealand were reviewed.

RESULTS

59,461 (65%) platelet components were sampled on Day 2 and 15,560 (17%) were re-sampled post-expiry, between December 2003 and September 2011. The rate of confirmed bacterial contamination was 0.04% for Day 2 sampling and 0.04% for post-expiry sampling. The rate in the published literature ranges from 0.01-0.74% and is lower (0.01-0.18%) when diversion of the initial flow of blood is utilised. There were five bacterial transfusion transmitted infections associated with platelet transfusion reported during the study period.

CONCLUSIONS

BacT/ALERT screening reduces the transfusion of bacterially contaminated platelet concentrates. Day 2 sampling does not identify all contaminated units.