Impact of Initial Specimen Diversion Technique on Blood Culture Contamination Rates

Dhammika Navarathna, Janell Lukey
Veterans Affairs Central Texas Healthcare System
Fed Pract. 2025;42(6):e0596. June 17. doi:10.12788/fp.0596

Background
A false-positive blood culture contamination rate of 3.0% is a widely recognized hospital benchmark. In November 2017, the Veterans Affairs Central Texas Healthcare System (VACTHCS), a 146-bed urban teaching hospital with about 30,000 annual emergency department (ED) visits, introduced the initial specimen diversion technique (ISDT) to reduce its contamination rate. ISDT uses blood draws to isolate and discard the initial portion of blood collected, known to be more prone to contamination from skin bacteria.

Methods
This retrospective comparative study of ISDT effectiveness was conducted at VACTHCS. Data were collected 36 months before and after ISDT implementation. Adults admitted to VACTHCS through the ED who required blood cultures for clinical suspicion of infection were included. Data were reviewed 36 months postimplementation to determine the effectiveness of the ISDT intervention.

Results
There was a marked decrease in contamination rates within the VACTHCS ED. Pre-implementation, the mean contamination rate was 4.5% (95% CI, 3.90-4.90), which decreased to 2.6% (95% CI, 2.10-3.20) following ISDT implementation (P < .001).

Conclusions
Targeted interventions such as ISDT may reduce blood culture contamination rates in the ED. Incorporating ISDT at VACTHCS resulted in an overall blood culture contamination reduction and improved patient care.

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