COVID-Anosmia Checker: A rapid and low-cost alternative tool for mass screening of COVID-19

Abstract

Background: Covid-19 curve can be flattened by adopting mass screening protocols with aggressive testing and isolating infected populations. The current approach largely depends on RT-PCR/rapid antigen tests that require expert personnel resulting in higher costs and reduced testing frequency. Loss of smell is reported as a major symptom of Covid-19, however, a precise olfactory testing tool to identify Covid-19 patient is still lacking. Methods: To quantitatively check for the loss of smell, we developed an odor strip, COVID-Anosmia checker, spotted with gradients of coffee and lemon grass oil. We validated its efficiency in healthy and COVID-19 positive subjects. A trial screening to identify SARS-CoV-2 infected persons was also carried out to check the sensitivity and specificity of our screening tool. Results: It was observed that COVID positive participants were hyposmic instead of being anosmic when they were subjected to smelling higher odor concentration. Our tool identified 97% of symptomatic and 94% of asymptomatic COVID-19 positive subjects after excluding most confounding factors like concurrent chronic sinusitis. Further, it was possible to reliably predict COVID-19 infection by calculating a loss of smell score with 100% specificity. We coupled this tool with a mobile application, which takes the input response from the user, and can readily categorize the user in the appropriate risk groups. Conclusion: Loss of smell can be used as a reliable marker for screening for Covid-19. Our tool can rapidly quantitate anosmia, hyposmia, parosmia, and can be used as a first-line screening tool to trace out Covid-19 infection effectively.

Anosmia Testing as Early Detection of SARS-CoV-2 Positivity; A Prospective Study under Screening Conditions

“…It is noteworthy that the scent test performance in terms of identifying SARS-CoV-2 infections is considerably lower than comparably published studies [ 23 , 24 ]. However, it should be mentioned that this study is one of the rare ones where the scent test was performed under screening conditions.…”

“…Previously, this at least partially specific symptomatology was used as an anamnestic screening tool, along with general symptoms of upper respiratory tract infection, such as cough, fever, and rhinitis. Based on studies showing the strongest association of olfactory impairment with COVID-19 compared with these other symptoms [ 21 , 22 ], commercially available scratch tests have been developed to test the sense of smell in an ambulatory and simple manner and to derive a conclusion about the likelihood of COVID-19 [ 23 ]. One such test was investigated in the study presented here and evaluated for its usefulness as a screening method.…”