The use of a diversion tube to reduce blood culture contamination - a "real-life" quality improvement intervention study.

BACKGROUND: Blood culture contamination is associated with health care costs and potential patient harm. Diversion of the initial blood specimen reduces blood culture contamination. We report results of the "real-life" clinical implementation of this technique.

METHODS: Following an educational campaign, use of a dedicated diversion tube was recommended prior to all blood cultures. Blood culture sets taken from adults using a diversion tube were defined as "diversion sets", those without, "non-diversion" sets. Blood culture contamination and true positive rates were compared for diversion and non-diversion sets and to non-diversion historical controls. A secondary analysis investigated efficacy of diversion by patient age.

RESULTS: Out of 20107 blood culture sets drawn, the diversion group included 12774 (60.5%) and the non-diversion group 8333 (39.5%) sets. The historical control group included 32472 sets. Comparing non-diversion to diversion, contamination decreased by 31% [5.5% (461/8333) to 3.8% (489/12744), p<0.0001]. Contamination was also 12% lower in diversion than historical controls [3.8% (489/12744) vs 4.3% (1396/33174) p=0.02)]. The rate of true bacteremia was similar. In older patients, contamination rate was higher, and the relative reduction associated with diversion decreased (54.3% amongst 20-40-year-olds vs 14.5% amongst >80-year-olds).

CONCLUSION: Use of a diversion tube in the ED reduced blood culture contamination in this large real life observational study. Efficacy decreased with increasing age, which requires further investigation.