Smell Tests to Evaluate olfactory Function at the POC: A Narrative Review of Clinical Utility

Olfactory dysfunction (OD) is increasingly recognized as a valuable clinical 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 importance, olfactory testing remains underutilized in routine clinical care due to challenges related to test accessibility, cultural adaptability, and practical implementation.This narrative review evaluates point-of-care (POC) olfactory tests, focusing on their diagnostic accuracy, administration methods, user-friendliness, and applicability across diverse clinical populations. A comprehensive literature search identified 176 studies published between 2014 and 2024 that examined both qualitative and quantitative olfactory assessments in adult and pediatric populations across global settings. The review covers widely used tests such as the University of Pennsylvania Smell Identification Test (UPSIT®), Sniffin’ Sticks®, SCENTinel®, the NIH Odor Identification Toolbox, and culturally adapted tools like the Barcelona Smell Test-24 (BAST-24).Findings reveal substantial variability in sensitivity, specificity, and feasibility among tests, underscoring the importance of selecting tools tailored to patient demographics, clinical context, and the underlying condition. While psychophysical tests continue to serve as the clinical gold standard, emerging digital and self-administered methods offer promising alternatives for home-based and remote use.The review concludes that the integration of validated, context-appropriate olfactory assessments into standard clinical workflows could significantly enhance early disease detection, inform treatment decisions, and ultimately improve the quality of life for individuals affected by olfactory dysfunction.