Objective evaluation of odor loss in COVID-19 and other suspected cases

Introduction

COVID-19 is a pandemic disease known with one of the symptoms is sudden onset anosmia. This symptom sometimes may be the only sign of the disease, therefore it must be research widely.

Objective

We aim to evaluate odor dysfunction in COVID-19 patients objectively and safely without any risk of transmitting the disease.

Methods

The odor threshold test was performed on 105 patients hospitalized at the XXXX Training and Research Hospital on the COVID-19 pandemic service before any treatment began. Odor threshold was tested using a modification of the Connecticut Chemosensory Clinical Research Center olfactory function test. COVID-19 signs and symptoms, PCR test results, thorax computed tomography (CT) findings, and length of hospital stay were recorded. Odor tests were scored between 0–8, 0–1 anosmia, 2–3 severely hyposmia, 4 moderate hyposmia, 5 mild hyposmia, 6 and above normosmia.

Results

Forty-one (39%) of the 105 patients were diagnosed with COVID-19 after the PCR results. Patients with an odor threshold score < 5 were classified as “Smell-Impaired Group”, patients with an odor threshold score ≥ 5 were placed in “Smell Intact Group”. The incidence of female patients in smell-impaired group was significantly higher (p ˂ 0.05). The proportion of patients who were PCR-positive for COVID-19 in smell-impaired group was significantly higher (p ˂ 0.05) than in smell intact group. Among patients with an odor threshold score from 0 to 1 (anosmic; n = 15), 12 (80%) demonstrated PCR positivity (p < 0.0001).

Conclusion

Anosmia can be predictive for coronavirus disease. Odor threshold test can be helpful for diagnosis.