This study was done at a single hospital and only with patients in intensive care units. The same results may not be found at different hospitals or with other types of patients. Chlorhexidine solution is clear, and povidone-iodine is brown; the nurses who drew the blood culture samples could therefore tell which solution they were using. It is possible that they cleaned the skin differently with the two solutions. Lastly, we do not know whether patients who had blood cultures done using chlorhexidine had better outcomes, such as shorter hospital stays, less unnecessary treatment with antibiotics, and fewer complications. The study also did not determine whether use of one cleaning solution was less expensive than use of the other.