Skin antiseptics in venous puncture-site disinfection for prevention of blood culture contamination: systematic review with meta-analysis

Blood cultures drawn by venous puncture are common clinical procedures for the detection of bacteraemia. Blood culture contamination (BCC) can lead to clinical misinterpretation and unnecessary expenses. We aimed to systematically review randomised controlled trials (RCTs) with skin antiseptics for prevention of contamination in venous-puncture drawn blood cultures. We conducted database search using CENTRAL (Cochrane Library issue April 2010), MEDLINE, EMBASE and mRCT, in June 2010. All RCTs testing skin antiseptics in venous-puncture drawn blood cultures were retrieved. Relative risk (RR) of the BCC outcome was analysed by random effects method using confidence interval (CI) of 95%. Studies were assessed by one review author and checked by another. Six studies were identified. Single-trial comparisons showed that alcoholic iodine tincture was better than non-alcoholic povidone-iodine, and isopropyl/acetone/povidone-iodine showed superiority against isopropyl/povidone-iodine. Meta-analysis demonstrated that alcoholic chlorhexidine was better than non-alcoholic povidone-iodine (RR: 0.33; 95% CI: 0.24-0.46) in 4757 blood cultures from two trials. Alcoholic solutions were better than non-alcoholic products (0.53; 0.31-0.90) in 21 300 blood cultures from four studies. Two trials with 13 418 blood cultures showed that iodine tincture was not superior to povidone-iodine in BCC prevention (0.79; 0.54-1.18). Alcoholic iodine was not different from non-alcoholic iodine (0.79; 0.53-1.17). Comparison of chlorhexidine vs iodine compounds was not conclusive. Alcohol alone was not inferior to iodinated products for prevention of contamination in venous-puncture drawn blood cultures. The association of alcohol and povidone-iodine did not seem to be useful. Alcoholic chlorhexidine solutions reduced blood culture false positives compared with aqueous povidone-iodine.