Overview

• Johns Hopkins–led researchers analyzed more than 360,000 blood cultures from 52 acute care hospitals across 19 states and Washington, D.C., collected between Sept. 2019 and Aug. 2021.
• Hospitals reported using varied criteria: 65.4% relied on CLSI/CAP definitions, 17.3% used local criteria, and 17.3% paired CLSI/CAP with the NHSN list, with about half targeting a contamination threshold below 3%.
• Mean contamination measured with CAP criteria was 1.38% in ICUs and 0.96% on wards, rising to 1.49% and 1.09% when the NHSN commensal list was applied.
• Higher contamination correlated with worse outcomes, with a 9% increase in CLABSI rates for every 1% increase in blood culture contamination.
• Only a minority of hospitals tracked complementary quality metrics such as number of bottles collected or blood culture positivity, reinforcing calls for broader monitoring and standardization.