Blood Culture Metrics Are Human Metrics: The Missed Opportunity for Clinical Laboratory Quality Measures to Improve the Overall Blood Culture Process

The human and organizational burdens of sepsis can be reduced by early recognition, diagnosis, therapy, and systems that support more effective management. The World Health Organization's (WHO's) 2020 Global Report on the Epidemiology and Burden of Sepsis will add importance to the clinical laboratory's role of monitoring blood culture metrics. The report details strategies for future efforts to characterize the global impact of sepsis more accurately, to improve the characterization of and differences in epidemiology, and to make estimates of disease burden more accurate. As the WHO is working toward improved global sepsis monitoring, re-assessment of the way clinical laboratories can contribute to this effort are long overdue at the local, national, and global levels.

Clinical laboratory dogma describes the importance of blood cultures (BCs) and optimization of BC processes, with documented impact on patient care. The BC is considered a first-line investigation for the microbiological diagnosis of sepsis, bacteremia, and fungemia and can detect a wide variety of microorganisms at a relatively low cost. Once microbes are detected in BC broth, subcultures yield microbial colonies for subsequent identification and antimicrobial susceptibility testing, and information is incorporated into the final BC result. However, the impact of BCs and the speed at which BCs are collected, incubated, and reported are minimized in the “surviving sepsis” literature, except for BC collection prior to the administration of antibiotics. Most hospital quality efforts focus on compliance with the 1-, 3-, and 6-h sepsis bundles with limited focus on the contribution of microbiology's role in rapid incubation, pathogen reporting, and other diagnostics that drive antimicrobial de-escalation and escalation protocols.

Clinical microbiology and laboratory medicine bear responsibility to ensure that BCs are collected properly and in a timely manner; that they are rapidly transported to the laboratory and incubated quickly; and that results are achieved and reported in a timely, reproducible, and accurate fashion. The quality metrics we discuss are not all required by inspection agencies; however, considering the initiatives to reduce the human cost of sepsis, attention to best practices is useful to optimize BC performance and BC yield. Examples of blood culture quality monitors and metrics are listed for laboratory consideration. Each laboratory may have unique situations in which one or more of the monitors may prove to be useful.