Utility of Olfactory test as screening tool for COVID-19: A pilot study

Loss of smell function (Anosmia) is reported to be associated with novel coronavirus disease 2019 (COVID-19) infection. The present study was designed to evaluate the effectiveness of an indigenously developed prototype smell test to identify/diagnose asymptomatic COVID-19 positive individuals. A panel of five different odorants belonging to Indian household with unique and mutually exclusive odor were used to develop prototype kit to test the hypothesis. The developed prototype kit was tested at 2 centers (N=49 and 34) with slight modifications. Simultaneously, the kit was also tested on 55 (N=35 and 20) healthy controls. Our results indicate that otherwise asymptomatic COVID-19 positive individuals were having quantifiable deficit in smell sensation. Interestingly, the variable sensitivity of different odorants was observed in different patients. None of the healthy controls reported difficulty in sensing any of the odorant, whereas, some of healthy controls did misidentify the odorants. Overall, the present study provides a preliminary data that loss in smell sensation for various odorants can be exploited as a quick and affordable screening test to identify infected cases among at risk individuals.