A Novel Application-Based Test for Rapid Screening of Olfactory Dysfunction

Olfactory dysfunction (OD) is a common and underdiagnosed condition that is associated with increased morbidity and mortality. However, existing smell tests can be costly and time intensive and can lack scalability.

To evaluate the performance of a novel, self-administered mobile application-based olfactory screening tool.

This diagnostic study was conducted at a tertiary academic medical center in the US between June 1 and December 31, 2024, to assess the performance of a novel olfactory test for the detection of OD. English-speaking individuals who were 18 years or older were recruited for the study.

Completion of a 5-item, mobile application-based smell identification test. A subset of participants also completed a comparator test.

Diagnostic performance of a novel smell identification test in detecting OD compared with that of a comparator test. Secondary outcomes included correlation with subjective olfactory function.

The study included 484 participants, 243 (50.2%) of whom were men. The mean (SD) age was 53.4 (18.5) years; 160 participants (33.1%) were 65 years or older. Seventy-four participants (15.3%) reported having subjective OD. Participants with self-reported OD had significantly lower novel test scores than those with normosmia (2.54 vs 3.50; mean difference, -0.96 [95% CI, -1.24 to -0.68]). At a cut point of less than 3, the novel test achieved an area under the curve of 0.87 (95% CI, 0.78-0.96), a sensitivity of 74% (95% CI, 51%-88%), and a specificity of 86% (95% CI, 72%-93%). Novel test scores correlated with comparator test scores (r = 0.74 [95% CI, 0.59-0.83]) as well as self-reported smell (r = 0.34 [95% CI, 0.25-0.41]), with acceptable internal consistency (Cronbach α = 0.70-0.71). Novel test scores declined with age, and women aged 18 to 29 years had higher scores than men in the same age group.

The findings of this diagnostic study suggest that the novel study test is a rapid and reliable olfactory screening tool that correlates well with validated smell tests and has potential for longitudinal screening of OD in the clinical setting.