From guesswork to guidelines: advancing diagnostic stewardship in immunocompromised hosts.

Diagnostic stewardship, the optimization of diagnostic testing to improve patient outcomes, is a rapidly evolving field; however, data relating to immunocompromised hosts are scarce. This review examines recent advances in diagnostic stewardship and explores best practice principles for key clinical scenarios in immunocompromised patients, including febrile neutropenia, central nervous system infections, invasive fungal infections, cytomegalovirus, and Clostridioides difficile. Key challenges remain, including optimizing test utilization without compromising patient safety, interpreting advanced diagnostics in the context of immunosuppression, and demonstrating cost-effectiveness. A multidisciplinary approach incorporating both diagnostic and antimicrobial stewardship principles is essential to improve outcomes in this complex patient population. Future research should focus on prospective evaluation of diagnostic stewardship interventions and their impact on clinical and economic outcomes in immunocompromised hosts.