Research Highlight

Device detects asymptomatic COVID-19 by testing sense of smell

doi:10.1038/nindia.2020.164 Published online 19 October 2020

Researchers have developed a fast and sensitive device that can help detect asymptomatic COVID-19 patients by testing their sense of smell1.

This device, the researchers say, could emerge as an economical screening option that people can use on their own.

“The instrument could deliver odorants in a controlled fashion, assessing the olfactory health status within 20 minutes,” says lead researcher Nixon M. Abraham from the Indian Institute of Science Education and Research (IISER) in Pune, India.

The device has built-in safety precautions to prevent cross-contamination, enabling it to safely quantify deficits in the sense of smell under infective conditions, Abraham says.  

The IISER scientists, teaming up with researchers from the Byramjee Jeejeebhoy Government Medical College and Sassoon General Hospitals in Pune, tested the efficiency of the instrument, which has a replaceable odour delivery unit.

They delivered 10 odorants of varying concentrations to normal healthy individuals and asymptomatic COVID-19 patients who tested positive as virus carriers. At low concentrations for all odours, the patients displayed reduced detection abilities compared with healthy ones. 

The researchers found that 82 per cent of the asymptomatic patients had olfactory dysfunctions and failed in detecting odorants at low concentrations while 65 per cent of them showed lower detection scores for all three concentrations tested. 

The device showed a sensitivity of above 70 per cent and specificity of above 90 per cent, indicating its potential and efficiency in detecting asymptomatic COVID-19 patients.


1. Bhattacharjee, A. S. et al. Quantitative assessment of olfactory dysfunction accurately detects asymptomatic COVID-19 carriers. EClinicalMedicine. (2020) doi: 10.1016/j.eclinm.2020.100575