Blood cultures ordered in the adult emergency department are rarely useful

Although blood cultures are commonly ordered in the emergency department, there is controversy about their utility. This study aimed to determine the usefulness of blood cultures in the management of patients presenting to a tertiary adult teaching hospital emergency department in Perth, Western Australia.

A detailed chart review was undertaken of all blood cultures taken in our emergency department over a 2-month period. All patients within the hospital having blood cultures taken were identified; from this group, blood cultures originating from the emergency department were reviewed. Data were collected concerning patient demographics, culture indication, vital signs, culture outcome, disposition and alterations in management resulting from the blood culture.

218 blood cultures were ordered from the emergency department during the study period. This represented 4.0% (218/5478) of the total number of patients seen. Of the 218 cultures, only 30 were positive (13% of the study population), with 16 (7.3%) probable contaminants and 14 (6.4 %) true positives. No anaerobic isolates were identified. Of the 14 significantly positive blood cultures, the result influenced management in six patients, resulting in a useful culture rate of 2.8% (6/218).

Blood cultures are ordered on a significant number of patients seen in the emergency department but rarely alter management. Our findings in conjunction with other studies suggest that eliminating blood cultures in immunocompetent patients with common illnesses such as urinary tract infection, community acquired pneumonia and cellulitis, may significantly reduce the number of blood cultures, producing substantial savings without jeopardizing patient care. This needs prospective study and validation.