Diagnostic Yield of Initial and Consecutive Blood Cultures in Children With Cancer and Febrile Neutropenia

Background The timing and necessity of repeated blood cultures (BCs) in children with cancer and febrile neutropenia (FN) are unknown. We evaluated the diagnostic yield of BCs collected pre- and post-empiric FN antibiotics. Methods Data collected prospectively from the Australian Predicting Infectious ComplicatioNs in Children with Cancer (PICNICC) study were used. Diagnostic yield was calculated as the number of FN episodes with a true bloodstream infection (BSI) detected divided by the number of FN episodes that had a BC taken. Results A BSI was identified in 13% of 858 FN episodes. The diagnostic yield of pre-antibiotic BCs was higher than of post-antibiotic cultures (12.3% vs 4.4%, P < .001). Two-thirds of the post-antibiotic BSIs were associated with a new episode of fever or clinical instability, and only 2 new BSIs were identified after 48 hours of empiric antibiotics and persistent fever. A contaminated BC was identified more frequently in post-antibiotic cultures. Conclusions In the absence of new fever or clinical instability, BCs beyond 48 hours of persistent fever have limited yield. Opportunity exists to optimize BC collection in this population and reduce the burden of unnecessary tests on patients, healthcare workers, and hospitals.