A simplified blood culture sampling protocol for reducing contamination and costs: a randomized controlled trial

Blood culture contamination carries risks for patients, such as unnecessary antimicrobial therapy and other additional hazards and costs. One method shown to be effective in reducing contamination is initial blood specimen diversion during collection. We hypothesized that initial blood specimen diversion without a designated device or procedure would suffice for reduction in blood culture contamination rate.

From 1 September 2017 through to 6 September 2018, we conducted a randomized controlled trial to assess the effect of an initial-specimen diversion technique (ISDT) on the rate of blood-culture contamination by changing the order of sampling using regular vacuum specimen tubes instead of commercially available sterile diversion devices. We included adults from whom the treating physician planned to take blood cultures and additional blood chemistry tests. Additionally, we evaluated the potential economic benefits of an ISDT. This was a researcher-initiated trial, Clinicaltrials.gov NCT03088865.

In all, 756 patients were enrolled. This method, compared with the standard procedure in use at our medical centre, reduced contamination by 66% (95% CI 17%-86%), from 20/400 (5%) with the standard method to 6/356 (1.6%) with the ISDT, without compromising detection of true bloodstream infection and at no additional cost. Hospital-wide implementation of ISDT was associated with a 1.1% saving in hospitalization days.

We offer this novel approach as a simple, cost-effective measure to reduce risks to patient safety from contaminated blood cultures, without the need for using costly devices.