[Routine written intervention asserting the advantages of multiple blood cultures increases their order rate among...

Obtaining two or more blood culture sets is important for achieving good sensitivity and for detecting contamination. However, many doctors still only order one set for their laboratory testing. We wished to determine if routine written intervention to these doctors could increase the number of multiple blood cultures they ordered.

On November 11, 2011 at Tokyo Teishin Hospital, we began sending letters asserting the advantages of using multiple blood culture sets to doctors who only ordered solitary blood cultures. The effect of the intervention was determined by measuring the order rate of multiple blood culture sets at the hospital. We compared the order rate one year before intervention with that of one year after. We used a chi-square test (without Yates correction) to analyze the data, and p values less than 0.05 were considered to be statistically significant; all tests were two-tailed.

Before written intervention, the order rate of multiple blood cultures was 41%. This increased significantly to 68% after intervention (p < 0.001). The latter figure was 1.7 times greater than the former (relative risk, 1.7; 95% confidence interval, 1.5-1.8).

Routine written educational intervention asserting the advantage of multiple blood cultures led to an increase in their order rate by doctors. While this is a significant increase, it is still insufficient. Therefore, we propose the need for internal policies requiring at least two blood culture sets to ensure better sensitivity and detection of contamination. To enforce these policies, hospital personnel should be allowed to routinely intervene by either sending warning letters to the doctors or displaying this information on the patient's electronic chart.