Reducing blood culture contamination in community hospital emergency departments: a multicenter evaluation of a quality improvement intervention

Acad Emerg Med. 2014 Mar;21(3):274-82. doi: 10.1111/acem.12337.


Objectives: Blood culture contamination is a common and preventable problem in the emergency department (ED). In a previous single-center study, changing the process of ED blood culture collection from the traditional "clean," nonsterile procedure to a fully sterile procedure with standardized use of sterile gloves, large-volume chlorhexidine skin antisepsis, and fenestrated sterile drapes resulted in a substantial reduction in contamination. The objective of the current study was to evaluate the effectiveness of this sterile blood culture collection process for reducing blood culture contamination in two community hospital EDs.

Methods: The authors implemented the sterile blood culture collection process in the ED of two hospitals, including Hospital A, which historically had a contamination rate of approximately 5%, and Hospital B, with a 2.5% historical contamination rate. With an interrupted times-series design and segmented regression analysis to adjust for secular trends and autocorrelation, the monthly percentages of cultures contaminated at each hospital during an intervention period (sterile technique) were compared to a 10-month baseline period immediately preceding implementation (clean technique). At Hospital A, the full sterile blood culture collection process was used throughout the 16-month intervention period. At Hospital B, user feedback indicated poor adherence to the process due to difficulty implementing the fenestrated drape component; therefore, the process was simplified to the modified sterile collection process, in which the fenestrated drape component was dropped and sterile gloves and large-volume skin antisepsis were emphasized. Hence, at Hospital B, two intervention periods were compared to the baseline period: the 8-month intervention period 1 (full sterile process) and the subsequent 8-month intervention period 2 (modified sterile process).

Results: At Hospital A, during the baseline period, 165 of 3,417 (4.83%) cultures were contaminated, while 142 of 5,238 (2.71%) were contaminated during the intervention period (p < 0.01). In the segmented regression model, the full sterile blood culture collection process was associated with an immediate 2.68% (95% confidence interval [CI] = 1.43% to 3.52%) absolute reduction in contamination and sustained reductions during the entire intervention period. At Hospital B, during the baseline, 63 of 2,509 (2.51%) cultures were contaminated. In intervention period 1 with the full sterile process, 51 of 1,865 (2.73%) cultures were contaminated (p = 0.65), with segmented regression results showing no changes compared to baseline. After simplification of the process to address poor adherence, the modified sterile process during intervention period 2 was associated with a significant reduction in contamination, with 17 of 1,860 (0.91%) cultures contaminated (p < 0.01 compared to baseline). The segmented regression model demonstrated the modified sterile process was associated with an immediate 1.53% (95% CI = 1.00% to 1.88%) absolute reduction in contamination with significant sustained reductions.

Conclusions: Changing the method of blood culture collection from the commonly used nonsterile technique to a sterile process resulted in significant reductions in blood culture contamination at two community hospital EDs, including one with low baseline contamination. Monitoring the implementation process at both sites was important to identify and overcome operational challenges. At one study site, simplification of the process by removing the fenestrated drape component was a key for successful implementation.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antisepsis / methods
  • Blood / microbiology
  • Blood Specimen Collection / adverse effects
  • Blood Specimen Collection / methods
  • Blood Specimen Collection / standards*
  • Chlorhexidine
  • Emergency Service, Hospital / standards
  • Hospitals, Community
  • Humans
  • Quality Improvement*


  • Chlorhexidine