Performance of formal smell testing and symptom screening for identifying SARSCoV- 2 infection

James W. Keck, Matthew Bush, Robert Razick, Setareh Mohammadie, Joshua Musalia, Joel Hamm

Research output: Contribution to journalArticlepeer-review


Background Altered sense of smell is a commonly reported COVID-19 symptom. The performance of smell testing to identify SARS-CoV-2 infection status is unknown. We measured the ability of formal smell testing to identify SARS-CoV-2 infection and compared its performance with symptom screening. Methods A convenience sample of emergency department patients with COVID-19 symptom screening participated in smell testing using an eight odor Pocket Smell Test (PST). Participants received a SARS-CoV-2 viral PCR test after smell testing and completed a health conditions survey. Descriptive analysis and receiver operating characteristic (ROC) curve models compared the accuracy of smell testing versus symptom screening in identifying SARS-CoV-2 infection. Results Two hundred and ninety-five patients completed smell testing and 87 (29.5%) had a positive SARS-CoV-2 PCR test. Twenty-eight of the SARS-CoV-2 positive patients (32.2%) and 49 of the SARS-CoV-2 negative patients (23.6%) reported at least one of seven screening symptoms (OR = 1.54, P = 0.13). SARS-CoV-2 positive patients were more likely to have hyposmia (≤5 correctly identified odors) than SARS-CoV-2 negative patients (56.1% vs. 19.3%, OR = 5.36, P<0.001). Hyposmia was 52.9% (95% CI 41.9%-63.7%) sensitive and 82.7% (95% CI 76.9%-87.6%) specific for SARS-CoV-2 infection. Presence of ≥1 screening symptom was 32.2% (95% CI 22.6%-43.1%) sensitive and 76.4% (70.1%-82.0%) specific for SARS-CoV-2 infection. The ROC curve for smell testing had an area under the curve (AUC) of 0.74 (95% CI 0.67-0.80). The ROC curve for symptom screening had lower discriminatory accuracy for SARS-CoV-2 infection (AUC = 0.55, 95% CI 0.49-0.61, P<0.001) than the smell testing ROC curve. Conclusion Smell testing was superior to symptom screening for identifying SARS-CoV-2 infection in our study.

Original languageEnglish
Article numbere0266912
JournalPLoS ONE
Issue number4 April
StatePublished - Apr 2022

Bibliographical note

Publisher Copyright:
© 2022 Keck et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

ASJC Scopus subject areas

  • General


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