Single-Set Blood Culture Restriction During the 2024 National Blood Culture Bottle Shortage: An Interrupted Time Series Analysis of Patient Outcomes
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Importance
The 2024 national blood culture bottle shortage led some hospitals to adopt single-set blood culture restrictions, conflicting with professional society guidance for 2–3 sets and risking underdiagnosis. Patient outcomes are not well studied.
Objective
To evaluate the impact of single-set blood culture restriction on patient outcomes, culture use, and antimicrobial therapy.
Design, Setting, and Participants
Interrupted time series analysis of 147,214 hospitalizations (36,909 with ≥1 blood culture) across 3 tertiary hospitals in an urban academic center, June 26, 2023–June 25, 2025. Periods were categorized as pre-restriction, restriction, and post-restriction. Analyses were conducted overall, among hospitalizations with ≥1 blood culture set (≥1-BC hospitalizations), and by hospital.
Exposure
Strict electronic health record order restriction limiting to 1 blood culture set per patient every 24 hours (June 26–December 23, 2024).
Main Outcomes and Measures
Primary outcomes included in-hospital mortality or hospice discharge, 30-day revisits, and length of stay (LOS). Secondary outcomes included blood culture metrics (positivity, number, timing, proportion with ≥1 culture) and receipt and days of antimicrobials. Odds or incidence rate ratios were reported.
Results
Among all hospitalizations, in-hospital mortality/hospice discharge declined pre-restriction (–1.3%/week, P<.001), plateaued during restriction (+0.6%/week, P=.33), and resumed decline post-restriction (–2.8%/week, P<.001). Among ≥1-BC hospitalizations, trends were similar, with additional 37.6% increase upon restriction onset (P=.005); LOS increased 14.9% upon restriction onset (P<.001) then decreased post-restriction (–0.9%/week, P<.001). 30-day revisits were unchanged. Overall culture positivity increased 37.8% upon restriction onset (P<.001) and decreased 27.1% upon restriction withdrawal (P<.001). The proportion of hospitalizations with ≥1 culture decreased 37.7% among all hospitalizations (P<.001) and mean number of cultures per hospitalization decreased 49.2% among ≥1-BC hospitalizations (P<.001) upon restriction onset, both partially rebounding afterward. Among ≥1-BC hospitalizations, time from admission to first culture collection and antimicrobial administration increased 72.2% (P<.001) and 21.5% (P=.001), respectively, upon restriction onset; antimicrobial use increased 24.9% upon restriction onset (P=.02) and decreased 14.7% upon post-restriction onset (P=.19).
Conclusions and Relevance
Single-set blood culture restriction was associated with decreased and delayed testing, delayed antimicrobial start, and increased in-hospital mortality/hospice discharge. Findings underscore the need for optimal diagnostic stewardship practices and supply-chain resiliency for critical diagnostic supplies.
Key Points
Question
What was the impact of restricting hospitals to 1 blood culture set per patient every 24 hours during the 2024 national shortage of blood culture bottles?
Findings
In this interrupted time series analysis of 147,214 hospitalizations (36,909 with ≥1 blood culture), single-set restriction was associated with decreased culture utilization, delays in time to obtaining cultures and antimicrobial administration, and increased in-hospital mortality/hospice discharge which interrupted otherwise declining trends.
Meaning
Single-set blood culture restrictions may impede detection of true bloodstream infections, delay antimicrobial prescribing, and worsen patient outcomes, underscoring the need for diagnostic stewardship and resilient supply chains for critical testing supplies.
