: development of a rapid test to screen for smell loss.

BACKGROUND

Commercially available smell tests are primarily used in research or in-depth clinical evaluations, but are too costly and lengthy for population surveillance in health emergencies like COVID-19. We developed the . test which rapidly evaluates three olfactory functions (detection, intensity, and identification). We tested whether self-administering the . test discriminates between individuals with smell loss or average smell ability (normosmics), and provides comparable performance as the validated and standardized NIH Toolbox Odor Identification Test in normosmics.

METHODS

Using Bayesian linear models and prognostic classification algorithms, we compared the . performance of a group of self-reported anosmics (N=111, 47±13yo, F=71%,) and normosmics (N=154, 47±14yo, F=74%), as well as individuals reporting other smell disorders (e.g., hyposmia, parosmia; N=42, 55±10yo, F=67%).

RESULTS

Ninety-four percent of normosmics met our . accuracy criteria, while only 10% of anosmics and 64% of individuals with other smell disorders did. Overall performance on . predicted belonging to the normosmic group better than identification or detection alone (vs. anosmic: AUC=0.95, Sensitivity=0.72, Specificity=0.94). Odor intensity provided the best single-feature predictor to classify normosmics. Among normosmics, 92% met the accuracy criteria at both . and the NIH Toolbox Odor Identification Test.

CONCLUSIONS

. is a practical test able to discriminate individuals with smell loss and is likely to be useful in many clinical situations, including COVID-19 symptom screening.