Diagnostics for (respiratory) viral infections are important for good treatment of the patient, but also for the purpose of good patient management in a (university) hospital. Proper isolation measures for example, to prevent other patients from becoming infected during hospitalization. Because new innovative diagnostics become available, critical diagnostic parameters are changing, such as quality, speed and costs. This dynamics creates new questions about how (hospital) laboratories should deal with this, in favor of healthcare institutions, but also for society. This became clear again during the covid-pandemic. New opportunities come with broader responsibilities, regarding proper use of diagnostics. A shift from the level of the ‘own’ institution – primarily for the benefit of the ‘own‘ patient – towards a shared responsibility for patients within the broader healthcare region; in a network of connected healthcare providers, like hospitals, long-term care facilities and general practitioners. In addition, a societal responsibility arises, both nationally and internationally. Knowledge about the options for diagnostics, outcome information, or epidemiological and clinically relevant information is essential, but sometimes only available to a limited extent at institutional level. Only close collaboration between (research) laboratories, healthcare institutions and (inter)national institutes of health such as the Dutch RIVM and the European CDC, will bring the field to the next phase. The dissertation ‘Diagnostic stewardship’ provides insights into this broader responsibility at the different levels. From (rapid) diagnostics in the hospital to a regional sequencing network and international developments, with the example of the upsurge of a virus that can cause paralysis in young children.