Inappropriate antibiotic prescribing can result in patient harm and costly antibiotic-resistant infections. Health record review of 1,477 patients admitted from the emergency department for suspected bacteremia infection revealed that 11.6% were misdiagnosed at infection site, and 3.1% did not have any infection. Misdiagnosis was not associated with worse short-term clinical outcomes but was associated with potentially inappropriate broad-spectrum antibiotic use.