Sites of blood collection and topical antiseptics associated with contaminated cultures: prospective observational study

We aimed to determine whether puncture sites for blood sampling and topical disinfectants are associated with rates of contaminated blood cultures in the emergency department (ED) of a single institution. This single-center, prospective observational study of 249 consecutive patients aged ≥ 20 years proceeded in the ED of a university hospital in Japan during 6 months. Pairs of blood samples were collected for aerobic and anaerobic culture from all patients in the ED. Physicians selected puncture sites and topical disinfectants according to their personal preference. We found 50 (20.1%) patients with potentially contaminated blood cultures. Fifty-six (22.5%) patients were true bacteremia and 143 (57.4%) patients were true negatives. Multivariate analysis associated more frequent contamination when puncture sites were disinfected with povidone-iodine than with alcohol/chlorhexidine (adjusted risk difference, 12.9%; 95% confidence interval [CI] 8.8–16.9; P