Despite multiple trials demonstrating that procalcitonin (PCT) is an effective tool for antibiotic stewardship, inconsistent application in real-world settings continues to fuel controversy regarding its clinical utility. We sought to determine rates of concordance between PCT results and antibiotic prescribing in hospitalized patients.
We performed a retrospective review of all inpatient encounters at an academic tertiary care health system with a PCT result between February 2017 and October 2019. Concordant prescribing was defined as starting or continuing antibiotics following an elevated PCT (>0.5 ng/mL) finding and withholding or stopping antibiotics following a low PCT (< 0.1 ng/mL) finding.
Antibiotic prescribing decisions were discordant from the PCT level in 32.5% of our sample. Among patients not receiving antibiotics at the time of testing, 25.9% (430 of 1,662) were prescribed antibiotics despite a low PCT result. Among patients already receiving antibiotics, treatment was continued despite a low PCT level in 80.4% (728 of 906) of cases. Enhanced decision support tools introduced during the study period had no impact on PCT use for antibiotic decisions.
Overall concordance between PCT results and antibiotic use is relatively low in a real-world setting. The potential value of PCT for antibiotic stewardship may not be fully realized.

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