Blood Culture Practices in Pediatric Intensive Care Units to Inform a Diagnostic Stewardship Intervention

Blood culture practice patterns, including blood culture indications and thresholds to culture based on patient-level factors, vary among pediatric intensive care units (PICUs) and pediatricians, and over-testing can be common.

Nine PICUs across the United States performed audits of randomly selected blood cultures in PICU patients across 4 seasons in a 12-month period. Cultures were audited for indication and associated clinical and patient-level factors. Sites applied their institutional guidelines to define fever and immunocompromised states. Data were analyzed to determine if certain culture indications were associated with sites' baseline blood culture rates.

In total, 1068 cultures were audited with a 6% positivity rate. New symptoms (such as fever, hypothermia, or concern for sepsis) accounted for most cultures obtained (71%), with concern for sepsis documented in about 38% of culture episodes. More than half of cultures were obtained despite a documented alternative source of symptoms. The practice of collecting asymptomatic or surveillance cultures was highly variable across sites, with 3 sites accounting for 84% of all asymptomatic cultures.

A large proportion of blood cultures in PICU patients were drawn for new symptoms, though often without a clear concern for sepsis and when an alternative source of symptoms was suspected or documented. Practices were variable regarding surveillance cultures. Work to develop and optimize thresholds and standard practices for sending cultures is critical to inform ongoing diagnostic stewardship efforts.