In 2023, the Society for Healthcare Epidemiology of America (SHEA) Task Force issued a practice recommendation on the integration of diagnostic stewardship into antibiotic stewardship (ABS) programs, which focuses on optimizing sample collection, processing, and reporting to ensure a correct test result on the one hand, and on the justifying indication to perform diagnostics on the other.Unnecessary microbiological or serological tests produce results that can then lead to unnecessary further tests for clarification or unnecessary antibiotic administration. A classic example is "routine" urine cultures before non-urological, surgical interventions, which often lead to the treatment of asymptomatic bacteriuria. Every microbiological diagnosis must therefore be preceded by a specific question, whereby screening examinations from epidemiological questions must be clearly distinguished from clinical requirements. A particular problem is the distinction between contamination, colonization and infection, especially when samples are taken from catheters or drains. These materials should always be evaluated with extreme caution and may only be accepted at all if the clinical question is clear and subject to this very reservation. This article summarizes the existing evidence on diagnostic stewardship interventions and recommendations on their implementation, extrapolating the international literature to the specifications of the German health care system.