Evaluation of donor skin disinfection methods

BACKGROUND: Because most bacteria isolated from contaminated platelet concentrates are thought to originate from the donor's skin, the efficacy of four methods of skin disinfection was compared. STUDY DESIGN AND METHODS: Contact plates were used for antecubital skin cultures after they were demonstrated to be easier to use and at least as sensitive as a swab system. One antecubital fossa of each subject was disinfected by a standard method, the use of a povidone‐iodine swabstick containing 0.75‐percent available iodine followed by the use of a povidone‐iodine swabstick containing 1‐percent available iodine. The other arm was disinfected with either a 70‐percent isopropyl alcohol scrub followed by an ampoule of 2‐percent iodine tincture (Group 1; n = 126); a green‐soap sponge followed by a 70‐percent isopropyl alcohol swab, used for donors who are allergic to iodine (Group 2; n = 30); or a 0.5‐percent chlorhexidine gluconate and 70‐percent isopropyl alcohol sponge followed by an ampoule of 0.5‐percent chlorhexidine gluconate and 70‐percent isopropyl alcohol (Group 3; n = 40). Contact plate cultures were done before and after disinfection, and colonies counted after a 48‐hour 37°C incubation period. RESULTS: Similar numbers of bacteria grew from both antecubital fossae of the same subject before disinfection (p = 0.71). Compared to the standard povidoneiodine method, isopropyl alcohol and tincture of iodine resulted in significantly less bacterial growth (p