Point-of-care smell testing for evaluation of olfactory function: a narrative review of clinical utility.

Importance: Olfactory dysfunction (OD) is increasingly recognized as a clinically relevant biomarker for a wide range of health conditions, including neurodegenerative diseases, respiratory infections such as COVID-19, psychiatric disorders, and age-related sensory decline. Despite its diagnostic value, olfactory testing remains underutilized in routine clinical care due to challenges related to test accessibility, cultural adaptability, cost and practical implementation. Observations: This narrative review provides a clinically focused synthesis of olfactory tests suitable for point-of-care (POC), focusing on their diagnostic accuracy, administration methods, user-friendliness, and applicability across diverse clinical populations. Commonly used tests such as the University of Pennsylvania Smell Identification Test (UPSIT®) and Sniffin' Sticks® are discussed alongside emerging rapid screening tools, pediatric assessments, and culturally adapted tests. Attention is given to distinguishing screening tools from comprehensive diagnostic batteries and to the role of point-of-care (POC) testing in primary care, neurology, and otorhinolaryngology settings. Practical considerations including assessment time, workflow feasibility, and clinical decision pathways are also examined. This review emphasizes the translation of available psychophysical tests into a practical POC framework for real-world clinical use. Conclusions and relevance: Available olfactory tests vary substantially in diagnostic accuracy, feasibility, and clinical applicability, highlighting the importance of selecting tests based on clinical indication and practice setting. Brief POC tests are best positioned as screening tools, while comprehensive batteries remain necessary when diagnostic precision is required. The main contribution of this review is a clinically oriented framework that distinguishes screening from diagnostic testing and aligns test selection with adult and pediatric clinical scenarios, workflow constraints, and referral needs. A tiered clinical approach using rapid screening followed by targeted comprehensive testing may represent the most practical, cost and time effective strategy for integrating olfactory assessment into routine care. Broader implementation of clinically feasible olfactory testing may improve early disease detection, support clinical decision making, and enhance patient care across conditions associated with OD.