• This work was carride out on behalf of the National Blood Service, Bacterial Contamination Reduction Project Team: S. Carrington, C. P. McDonald, E. Harvey, K. Burbridge, E. Williams, J. Butler, M. Spooner and P. Wilcox.

C. P. McDonald, National Bacteriology Laboratory, National Blood Service, North London, Colindale Avenue, London NW9 5BG, UK E-mail: carl.mcdonald@nbs.nhs.uk


Background and Objectives  The aim of this study was to demonstrate the efficiency of diverting the initial 20-ml donation from the collection bag and of an improved donor-arm disinfection procedure in reducing bacterial contamination in blood.

Materials and Methods  Donations were collected in bags specially manufactured for the study. These bags incorporated two satellite pouches into each of which 20 ml of blood was collected. Blood initially flowed into sample pouch P1, representing a diversion pouch. Pouch P2 was then filled with 20 ml of blood, which allowed us to sample the collection bag after diversion was complete. Blood then flowed into the standard collection bag. The contents of the pouches were aerobically and anaerobically cultured on the BacT/ALERT automated culture system for 7 days. Two procedures were investigated in the study (each involving 1409 blood donations): one analysed the current disinfection procedure; and the other analysed an improved donor-arm disinfection procedure.

Results  The use of diversion alone resulted in a 47% reduction in contamination, and improved donor-arm disinfection alone resulted in a 57% reduction in contamination. Diversion plus improved donor-arm disinfection produced a predicted 77% reduction in contamination.

Conclusions  The study validates diversion and an improved donor-arm disinfection procedure. In combination, these two interventions produced a substantial reduction in contamination. These procedures are to be introduced by the English National Blood Service to enhance the safety of the blood supply.