Diagnostic stewardship as the heart of clinical microbiology: a position paper of the French Society for Microbiology (SFM).

Caring about the clinical impact of laboratory results, beyond their technical performance, has been part of the clinical microbiologist's mission since the very origins of the discipline. The term diagnostic stewardship is more recent, emerging from a renewed need created by powerful new diagnostic technologies: as testing becomes faster, more sensitive and more widely used, results grow harder to interpret and easier to misuse. A result reported without interpretation is not neutral, and diagnostic misuse readily translates into inappropriate antibiotic use, making the laboratory an unrecognised driver of antibiotic prescription, while microbiologists have ever less time for clinical engagement. Diagnostic stewardship is thus a universal challenge, with a scope that extends well beyond antimicrobial use to virology, mycology, outbreak management, screening programs and infection prevention and control. In this position statement, the French Society for Microbiology argues that diagnostic stewardship is a core mission of clinical microbiologists and calls for the microbiologist to be repositioned as an active clinical actor rather than a passive provider of results. We discuss how this role varies across healthcare systems, notably between the United States and Europe. We propose concrete actions at the individual, laboratory and national levels. These actions are generalizable to other settings, provided they are adapted to the local context. We argue that the main obstacle is structural: when laboratory activity is measured and funded by test volume, the interpretive work that turns results into sound medical decisions goes unrewarded. While we focus on hospital practice, these principles apply equally to community settings. Recognising and supporting this distinctive clinical role of microbiologists is now essential.