Rapid diagnostic tests (RDTs) can speed the etiologic diagnosis of infections in several scenarios (e.g., sepsis, respiratory tract infections, and meningitis). Interpretation of currently available RDTs is not always straightforward, and therefore, they cannot yet replace conventional tests. Institutional priorities, integration with laboratory workflow, and cost are issues that have to be considered when selecting RDTs to implement locally. RDTs can improve antimicrobial prescribing at the institutional level if the antimicrobial stewardship team is actively involved; however, this should always be monitored. Available biomarkers for infection detection, mainly C-reactive protein (CRP) and procalcitonin (PCT), are useful when applied appropriately, to reduce antibiotic exposure in both the outpatient and inpatient setting, especially for acute respiratory tract infections. Biomarkers have to be used in combination with other available tools to diagnose infection, including the clinical scenario (outpatient, inpatient, and ICU), the pretest probability of infection, and patients' individual circumstances (i.e., immunocompromised or source of infection).