Objective: To assess the efficacy of the Yale Observation Scale (YOS) in detecting occult bacteremia in febrile, ambulatory pediatric patients with no apparent signs or symptoms of severe infection and with no focal infection.
Design: YOS scores were assigned as part of a prospective, multicenter, randomized, interventional trial of oral and intramuscular antibiotics in preventing the complications of occult bacteremia in febrile children.
Setting: Pediatric emergency departments at eight urban medical centers.
Participants: Children, 3 to 36 months of age with a temperature at least 39.0 degrees C, a nonfocal, non-toxic-appearing illness (or uncomplicated otitis media), treated as outpatients.
Results: There were 6611 assessable patients, who had both a blood culture result and a YOS score assigned. The median YOS score for both patients with bacteremia (n = 192) and patients without bacteremia (n = 6419) was 6, but the mean rank among patients with bacteremia was significantly higher (p < 0.0001). The sensitivity, specificity, and positive and negative predictive values for a YOS score greater than 10 were 5.2%, 96.7%, 4.5%, and 97.1%, respectively.
Conclusions: The YOS scores are higher among patients with bacteremia than among patients without bacteremia, but the difference is not clinically useful in detecting occult bacteremia in febrile children, with nonfocal, apparently nontoxic infection, treated as outpatients in this age group.