Diagnostic Yield of Repeat Blood Cultures and Risk Factors for Bloodstream Infection in Persistent Febrile...

The optimal frequency of repeat blood cultures in persistent febrile neutropenia (FN) remains unknown. This study aims to identify opportunities for blood culture diagnostic stewardship in persistent FN.

This is a retrospective cohort study of patients with hematology/oncology diagnoses and an FN episode >3 days. Generalized estimating equation logistic regression models were used to evaluate risk factors for new bloodstream infection (BSI) after FN day 3.

Among 620 patients, median FN duration was 5 days and median blood culture bottles collected per patient was 12. On FN day 1, 25% of patients had a positive blood culture; on FN days 2-9, <5% of patients per day had a new organism isolated. Among 31 new organisms isolated after FN day 3, 8 (26%) were contaminants. Of 503 patients with ≥1 blood culture collected after FN day 3, 19 (4%) had a new BSI after FN day 3. FN onset in the peri-hematopoietic cell transplant (HCT) period (day -7 to +30) was associated with lower odds of new BSI after FN day 3 (OR 0.18; 95%CI [0.04-0.71]; p=0.01).Thirty-six patients died within 30 days after FN day 3, including 4 with a new BSI after FN day 3; 1 death was attributable to BSI after FN day 3.

Detection of new BSI after FN day 3 was uncommon, demonstrating low diagnostic yield of repeat blood cultures after FN day 3. FN episodes in the peri-HCT period may be a potential focus for blood culture diagnostic stewardship initiatives.