The value of outpatient blood cultures in the emergency department.

The value of adult outpatient blood cultures was assessed by a retrospective chart review of all patients for whom cultures were obtained in an emergency department. Eighty-six of 411 patients for whom cultures were obtained were not admitted. Five of these 86 patients were identified as being bacteremic by positive blood culture growth the next day, and three of the five had endocarditis. All endocarditis patients had identifiable risk factors for this disease. Although blood cultures cannot be recommended for most patients discharged from the emergency department with a febrile illness, they are helpful in detecting endocarditis and other bacteremic conditions before obvious signs develop.