IMPACT OF A FALSE-POSITIVE BLOOD CULTURE RESULT ON THE MANAGEMENT OF FEBRILE CHILDREN

Objective. To evaluate the impact of a preliminary positive blood cult ure result, subsequently confirmed to be a false positive blood cultur e result on rate of hospitalization, antibiotic therapy and use of mic robiologic tests. Design. Retrospective chart review. Patients and met hods. Children between 1 month and 18 years old art whom a blood cultu re was performed were eligible, excluding those with an underlying con dition for whom a false positive blood culture may be difficult to ass ess, During the 1-year study period 9959 blood cultures were performed of which 778 (7.8%) produced growth, Charts of 81 patients with a fal se positive blood culture were reviewed and compared with those of 162 patients with true negative blood culture, Patients already hospitali zed when blood culture was drawn (n = 24) were analyzed separately fro m those who were not (n = 219), Among these, patients were divided int o those who were followed as outpatients (n = 104) and hospitalized (n = 115). Results. Both groups (false positive vs. true negative) were comparable for age, sex, temperature at consultation, white blood cell count and illness severity, Twenty-six percent of patients followed a s outpatients who had a false positive blood culture were hospitalized because of a preliminary positive blood culture result. Among patient s hospitalized at the initial assessment, the frequency of antibiotic therapy (91% vs. 71%, P < 0.01), the frequency of use of intravenous a ntibiotics (80% vs. 58%, P < 0.01) and the percentage of unwarranted a ntibiotic prescription (13% vs. 0%, P < 0.01) were significantly great er in the false positive group than in the true negative group, The sa me results were found for each of these outcomes among the group of pa tients followed as outpatients (61% vs. 28%, P < 0.01, 17% vs. 0%, P < 0.01 and 39% vs. 0%, P < 0.01) for false positive vs. true negative, respectively. Patients with false positive blood cultures had more blo od cultures drawn subsequently (P < 0.01). Children already hospitaliz ed when the blood culture was obtained did not show significant differ ences in main outcomes, Conclusions. False positive blood culture resu lts generate unnecessary hospitalizations, antibiotic therapy and use of microbiologic tests.