Emergency Department Observes 83% Reduction in Blood Culture Contamination with Initial Specimen Diversion Technology Adoption

Abstract

Background Blood culture attempts to reduce unfavorable outcomes for patients with bloodstream infections by guiding antibiotic therapy. False positive blood culture results are frequent (a 3% contamination rate is considered standard) and associated with unnecessary broad-spectrum antibiotic usage, extended hospital stays and elevated clinical costs. Diversion of the initial portion of a blood sample (which can host deep skin flora associated with venipuncture-dislodged skin fragments) is proposed to address an avenue for contamination unaddressed by conventional blood culture protocol. Methods Blood culture sets were obtained from adult patients during an 18-month observation period in a 32-bed emergency department in California for a non-randomized prospective controlled cohort study. Blood cultures were obtained using either conventional methods (venipuncture and intravenous catheter start) or with initial specimen diversion technology (in tandem with venipuncture and intravenous catheter start). Blood culture bottle tops were disinfected with alcohol pads and patient skin was prepared with a 30-second chlorhexidine gluconate solution scrub. Samples were considered contaminated if skin flora were present in either the aerobic or anaerobic bottle of a single blood culture set. Results Conventional methods were utilized to collect 3,170 blood cultures, from which 77 (2.43%) were contaminated, while initial specimen diversion technology was utilized to collect 2,168 blood cultures, from which 9 (0.42%) were contaminated. Conclusions Use of initial specimen diversion technology was associated with an 83% lower rate of blood culture contamination compared to conventional methods, sustained for 18 months. Lower rates of blood culture contamination translate to reduced administration of unnecessary antibiotics (diagnostic stewardship and antimicrobial stewardship), reduced patient length of stay, and reduced clinical expenditures.