A randomized trial of povidone-iodine compared with iodine tincture for venipuncture site disinfection: Effects on rates of blood culture contamination

BACKGROUND: Contamination of blood cultures creates problems in their inter pretation and unneeded resource utilization. Because skin flora comprise th e major group of contaminant species, more effective skin disinfection at t he venipuncture site could reduce contamination. SUBJECTS AND METHODS: We performed a randomized trial in adult inpatients a t a tertiary care teaching hospital. Antecubital venipuncture sites were ra ndomly disinfected with povidone-iodine or iodine tincture, and blood cultu res (two bottles, 10 mt of blood) were drawn by professional phlebotomists. Scoring of contaminant species was restricted to skin flora. Hospital reso urce utilization was compared among patients with contaminated blood cultur es and those with sterile blood cultures. RESULTS: Of the 3,851 blood cultures collected during the study, 120 (3.1%) were contaminated with skin flora. The contamination rate for blood cultur es collected after povidone-iodine was 3.8% (74 of 1,947), compared with a rate of 2.4% (46 of 1,904, P = 0.01) after iodine tincture. The difference in mean total hospital costs for patients with contaminated blood cultures and those with sterile blood cultures was $4,100 (95% confidence interval: $740 to $7,400, P = 0.02). CONCLUSIONS: Iodine tincture is superior to povidone-iodine for venipunctur e site antisepsis before blood culture sampling. Because of the high costs associated with contaminated blood cultures, hospitals should consider swit ching from povidone-iodine to iodine tincture. Reduction of the contaminati on rate may improve the quality of patient care and reduce hospital costs. (C) 1999 by Excerpta Medica, Inc.