Isopropyl alcohol is as efficient as chlorhexidine to prevent contamination of blood cultures

Background False-positive blood cultures can lead to unnecessary risks and misuse of antibiotics; to reduce rates of false-positives, it would be useful to determine whether use of an antiseptic with a prolonged effect is required. Methods Clinical study of efficacy (blinded and randomized) to compare the rate of blood culture contamination when skin antisepsis was performed with 70% isopropyl alcohol or 2% chlorhexidine gluconate in 70% isopropyl alcohol in 2 hospitals. Patients aged 16 years or older with suspected bloodstream infection who were allocated in the emergency room, internal medicine ward, or intensive care unit were included. Results Five of 563 (0.9%) blood cultures from the isopropyl arm and 10 of 539 (1.9%) from the chlorhexidine arm were contaminated. No significant differences were observed among the rate of contamination (χ 2 = 1.27; P  = .3) or the relative risk of contamination (relative risk = 2.09; 95% confidence interval, 0.72-6.07; P  = .2). Conclusions The rates of blood contamination were not different when isopropyl alcohol and chlorhexidine were compared. Isopropyl alcohol could be used for skin antisepsis before blood collection.