Evaluation of the Scansystem method for detection of bacterially contaminated platelets

Abstract

Platelet (PLT) bacterial contamination occurs in approximately 1 in 2000 PLT units. The College of American Pathologists recommends and AABB requires procedures to detect PLT bacterial contamination. Although two methods, BacT/ALERT (bioMerieux) and Pall BDS (Pall Corporation), have FDA approval for quality control testing, additional methods are in development. One such method was evaluated, the Scansystem (Hemosystem), which has been developed for use on leukoreduced PLT components between 30 and 72 hours after collection. Leukoreduced, single-donor apheresis PLT units (LR-SDPs) were inoculated with 10 bacterial species (low and high inocula) associated with PLT contamination. Bacterial detection was compared with the Scansystem and BacT/ALERT. Testing was initiated (10 replicates performed) when LR-SDPs were experimentally inoculated with bacteria. The Scansystem was evaluated 30 hours later, the shortest manufacturer recommended time after PLT collection. All replicates were positive with the Scansystem at 30 hours and with the BacT/ALERT, at 9.3 to 24.0 hours after inoculation. The Scansystem detected bacteria in 83 of 200 replicates (42%) at the time of inoculation indicating a potential for earlier application. The Scansystem, used to test LR-SDPs 30 hours after bacterial inoculation, detected all 20 replicates with a sensitivity equal to the BacT/ALERT system. Based on use of Scansystem with LR-SDPs 30 hours after collection and the BacT/ALERT being inoculated 24 hours after collection and incubated for an additional 24 hours before being determined to be negative, the Scansystem will potentially provide results at an earlier time point (32 hr) than provided by the BacT/ALERT system (48 hr).