The effect of skin disinfection materials on reducing blood culture contamination

Contaminated blood cultures may cause results to be misinterpreted, create unnecessary work for the laboratory, and increase costs. Disinfection of the venipuncture site is considered to be necessary for preventing contamination, although there is little information about the effectiveness of using different disinfection materials. The use of 70% isopropyl pads and povidone iodine saturated swabs (conventional method) was compared with the use of a 70% isopropyl/10% acetone scrub and povidone iodine dispenser (PREP method) for skin disinfection. Blood culture "kits" were prepared--bags containing collection tubes, instructions, and either conventional or PREP materials and were distributed randomly. The contents were concealed by a cover to prevent the user from selecting a specific type of decontamination kit. The kits were identified in the laboratory by color-coded labels on the collection tubes. Among 1,546 specimens evaluated, the contamination rate observed with conventional disinfection was significantly higher (4.6%; N = 763) than with PREP materials (2.2%; N = 783, P = 0.011) and was equivalent to the preceding 6-month contamination rate (4.7%). The lower contamination rate may be associated with greater effectiveness of a scrub or isopropyl/acetone solution, or both. Decontamination materials may have a significant impact on reducing blood culture contaminants from skin flora.