Validation of the Hospital for Sick Children Algorithm for Discriminating Bacteremia From Contaminants in Children With a Preliminary Positive Blood Culture

Abstract

ObjectivesChildren with positive blood cultures obtained in the emergency department (ED) prompt urgent actions due to the risk of bacteremia. This study aimed to validate the Hospital for Sick Children (HSC) algorithm used for discriminating bacteremia from contaminants, and identified variables associated with bacteremia in children with positive blood cultures. MethodsWe conducted a retrospective cohort study of all children with positive blood cultures from a tertiary care, pediatric ED between 2018 and 2022. A two-step standardized approach defined true bacteremia as the primary outcome based on 1) the bacteria involved and 2) the clinical outcome assessed by two reviewers. We evaluated multiple independent variables. We used multiple logistic regression to analyze the association between independent variables and outcome. ResultsAmong the 375,428 ED visits, 574 participants were identified; 286 (49.8%; 95%CI: 45.8-53.9%) with bacteremia and 288 (50.2%; 95%CI: 46.1-54.3%) contaminants. The algorithm identified 364 children (63.4%) at high risk of bacteremia, 178 (31.0%) at medium risk, and 32 (5.6%) at low risk. Corresponding bacteremia probabilities were 62%, 34%, and 0% for a sensitivity of 100% and a specificity of 11%. Suspicion of osteoarticular infection (aOR: 43.6; 95%CI: 16.2-118), presence of internal hardware (aOR: 24.9; 95%CI: 7.2-83.5), and presence of Gram-negative bacteria or Gram-positive cocci in chains/pairs (aOR: 21.7; 95%CI: 11.7-40.3) were the most significant predictors of true bacteremia. ConclusionThe Hospital for Sick Children algorithm is 100% sensitive to detect children with bacteremia but demonstrated low specificity at 11%. We identified predictors to discriminate contaminants from bacteremia.