Use of blood cultures in the emergency department

While the use of blood cultures to detect septicemia is a time-honored and valuable laboratory technique, guidelines for obtaining such cultures are vague. Several controversies exist regarding the utilization of blood cultures in the ambulatory setting, including when and on whom cultures should be obtained, how many cultures should be obtained, and how much blood should be obtained with each venipuncture. The guidelines have become slightly more confusing with the recognition of an entity known as occult bacteremia. A number of studies that bear relevance to these issues are reviewed. The utility of obtaining blood cultures in the ambulatory setting is examined, and guidelines are offered for obtaining blood cultures in adult and pediatric populations. Areas in which further research may be appropriate also are noted.