Blood cultures (BCx) are important for selecting appropriate antibiotic treatment. Ordering BCx for conditions with a low probability of bacteremia has limited utility, thus improved guidance for ordering BCx is needed. Inpatient studies have implemented BCx algorithms, but no studies examine the intervention in an Emergency Department (ED) setting.

We performed a quasi-experimental pre and postintervention study from January 12, 2020, to October 31, 2023, at a single academic adult ED and implemented a BCx algorithm. The primary outcome was the blood culture event rates (BCE per 100 ED admissions) pre and postintervention. Secondary outcomes included adverse event rates (30-day ED and hospital readmission and antibiotic days of therapy). Seven ED physicians and APP reviewed BCx for appropriateness, with monthly feedback provided to ED leadership and physicians.

After the BCx algorithm implementation, the BCE rate decreased from 12.17 BCE/100 ED admissions to 10.50 BCE/100 ED admissions. Of the 3,478 reviewed BCE, we adjudicated 2,153 BCE (62%) as appropriate, 653 (19%) as inappropriate, and 672 (19%) as uncertain. Adverse safety events were not statistically different pre and postintervention.

Implementation of an ED BCx algorithm demonstrated a reduction in BCE, without increased adverse safety events. Future studies should compare outcomes of BCx algorithm implementation in a community hospital ED without intensive chart review.