Skin disinfection methods: prospective evaluation and postimplementation results

BACKGROUND: Optimal skin disinfection ensures blood safety. In this study, efficacies of the two-step skin disinfection methods used at Canadian Blood Services (CBS) and two one-step methods produced by different manufacturers were compared. STUDY DESIGN AND METHODS: In each of the three phases of the study, two methods were compared by disinfection of the antecubital fossae of study subjects. The two-step methods were compared in Phase I: Method A (isopropyl alcohol scrub and iodine tincture ampule) and Method B (isopropyl alcohol and chlorhexidine scrub and isopropyl alcohol and chlorhexidine ampule). In Phases II and III, Method B was compared to two different one-step swab sticks containing isopropyl alcohol and chlorhexidine (Methods C and D). Contact plates were applied on each of the subjects before and after disinfection and incubated at 37 degrees C for 24 hours followed by colony counting. RESULTS: In 99% of the subjects, colonies per plate were reduced from approximately 60 to less than 10 after disinfection using any method. Method B was superior to Method A (p < 0.05) but was not significantly different from Methods C and D. Method D was implemented for skin disinfection at CBS with no significant effects on blood product contamination. Skin reactions increased from approximately 0.02% to approximately 0.62% after implementation, which were subsequently reduced to approximately 0.04%. CONCLUSION: In this study, isopropyl alcohol and chlorhexidine disinfectants were more efficacious than isopropyl alcohol and iodine. There was no difference in efficacy between one-step and two-step procedures or between methods of application. A one-step chlorhexidine and isopropyl alcohol kit has been successfully implemented at CBS.