Five-item odorant test as an indicator of COVID-19 infection in a general population

To analyze the utility of a 5-item odorant test (U-Smell-It™) in determining COVID-19 status in COVID-19 polymerase chain reaction (PCR)-positive and -negative participants.

Symptoms, COVID-19 status, and 5-item odorant test results were collected from general population COVID-19 testing in Louisiana (n = 1042), and routine COVID-19 screening of healthcare workers in a nursing home in Florida (n = 278) (ClinicalTrials.gov Identifier: NCT04431908).

In the general population COVID-19 testing site, a cutoff point of ≤2 (0, 1, or 2 correct answers out of 5) achieved sensitivity of 40.0% (95% CI: 26.4%-54.8%) and specificity of 89.2% (95% CI: 87.1%-91.1%) in detecting COVID-19 infection. Within this population, analysis of individuals with no self-reported loss of smell/taste and runny/stuffy nose resulted in sensitivity of 38.1% (95% CI: 18.1%-61.6%) and specificity of 92.3% (95% CI: 89.1%-93.4%), while analysis of individuals with self-reported loss of smell/taste and/or runny/stuffy nose resulted in sensitivity of 41.4% (95% CI: 23.5%-61.1%) and specificity of 82.4% (95% CI: 77.7%-86.5%).

The quick turnaround time, low cost, reduced resource requirement, and ease of administering odorant tests provide many advantages as an indicator sign to help flag a molecular diagnostic COVID-19 test with relatively high specificity. Our results suggest that this odorant testing for olfactory dysfunction may be a viable option in pre-screening COVID-19 infection. This tool has the potential to allow for continued monitoring and surveillance, while helping mitigate surges of COVID-19 variants. Further investigation is warranted to observe the extent to which odorant testing might be applied in a serial testing scenario.