Predictive Value of Sudden Olfactory Loss in the Diagnosis of COVID-19

• Published in: O.R.L. Journal for oto-rhino-laryngology and its related specialties 2020-07, Vol.82 (4), p.175-180
• Main Authors: Haehner, Antje, Draf, Julia, Dräger, Sarah, de With, Katja, Hummel, Thomas
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Betacoronavirus; Clinical Laboratory Techniques; Cohort Studies; Coronavirus Infections - complications; Coronavirus Infections - diagnosis; COVID-19; COVID-19 Testing; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Olfaction Disorders - diagnosis; Olfaction Disorders - epidemiology; Olfaction Disorders - etiology; Pandemics; Pneumonia, Viral - complications; Pneumonia, Viral - diagnosis; SARS-CoV-2; Sensitivity and Specificity; Smell and Taste Corner; Symptom Assessment; Young Adult
• ISSN: 0301-1569; 1423-0275
• DOI: 10.1159/000509143

Introduction: Recent reports suggest that sudden smell loss might be a symptom of SARS-CoV-2 infection. The aim of this study was to investigate the frequency of olfactory loss in an outpatient population who presented to a coronavirus testing center during a 2-week period and to evaluate the diagnostic value of the symptom “sudden smell loss” for screening procedures. Methods: In this cross-sectional controlled cohort study, 500 patients who presented with symptoms of a common cold to a corona testing center and fulfilled corona testing criteria completed a standardized diagnostic questionnaire which included the patients’ main symptoms, time course, and an additional self-assessment of the patients’ current smell, taste function, and nasal breathing compared to the level before the onset of symptoms. Results: Out of the 500 patients, 69 presented with olfactory loss. Twenty-two of them subsequently tested positive for SARS-CoV-2. Only 12 out of the patients without olfactory loss tested positive, resulting in a frequency of 64.7% for the symptom “sudden smell loss” in COVID-19 patients. Compared to COVID-19 patients without smell loss, they were significantly younger and less severely affected. Changes in nasal airflow were significantly more pronounced in SARS-CoV-2 negative patients with olfactory complaints compared to the patients with smell loss who tested positive for SARS-CoV-2. By excluding patients with a blocked nose, the symptom “sudden smell loss” can be attested a high specificity (97%) and a sensitivity of 65% with a positive predictive value of 63% and negative predictive value of 97% for COVID-19. Conclusion: Considering the high frequency of smell loss in non-hospitalized COVID-19 patients, acute olfactory impairment should be recognized as an early symptom of the disease and should be tested for on a regular basis. In contrast to other acute viral smell impairment, COVID-19-associated smell loss seems to be only rarely accompanied by a severely blocked nose.