BRIEF COMMUNICATIONS Chlorhexidine Compared with Povidone-Iodine as Skin Preparation before Blood Culture A Randomized, Controlled Trial

For author affiliations and current addresses, see end of text. C of blood cultures is common because microflora are usually present on the skin. The misinformation that results from contamination of blood cultures may have deleterious consequences. Therefore, it is important that blood cultures be collected by using a procedure that minimizes contamination (1). In general, preparation of the skin with one or more antiseptic agents should permit satisfactory antisepsis, provided that a suitable period (0.5 to 2 minutes) is allowed for the antiseptic to take effect (2). In many hospitals, however, the personnel collecting blood cultures do not carefully follow the recommended procedures, leading to an excessively high rate of blood culture contamination. This is especially true in the intensive care unit, possibly because of the high workload of nurses (2). A recent trial comparing povidone-iodine and iodine tincture antiseptics showed a substantially lower rate of blood culture contamination with use of iodine tincture; this finding was related to the fact that iodine tincture acts faster than povidoneiodine (1). However, use of iodine tincture in the intensive care unit is limited because repeated exposure to high concentrations of iodine can be toxic (3). Alternately, chlorhexidine has been found to be superior to povidone-iodine and alcohol when it is used for catheter care (3–5), but its value in preventing blood culture contamination remains unknown. We assumed that the decreased effectiveness of aqueous 10% povidone-iodine in previous studies could be related to the time required to achieve skin antisepsis with this agent. We examined whether the use of alcoholic chlorhexidine decreased the rate of blood culture contamination in hospitals in which personnel did not consistently allow antiseptics to act for the recommended time period before collection.