PT  - JOURNAL ARTICLE
AU  - O’Neill, Braden
AU  - Kalia, Sumeet
AU  - Gill, Peter
AU  - Hum, Susan
AU  - Moran-Venegas, Carla
AU  - Stoller, Rebecca
AU  - Greiver, Michelle
AU  - Agarwal, Payal
AU  - Kirubarajan, Abirami
AU  - DeKoven, Samuel
AU  - Eisen, David
AU  - Pinto, Andrew
AU  - Dunn, Sheila
TI  - Association between new-onset anosmia and positive SARS-CoV-2 tests among people accessing outpatient testing in Toronto, Ontario: a retrospective cross-sectional study
AID  - 10.9778/cmajo.20210085
DP  - 2021 Oct 01
TA  - CMAJ Open
PG  - E1134--E1140
VI  - 9
IP  - 4
4099  - http://www.cmajopen.ca/content/9/4/E1134.short
4100  - http://www.cmajopen.ca/content/9/4/E1134.full
SO  - CMAJ2021 Oct 01; 9
AB  - Background: Reports have suggested that anosmia is strongly associated with SARS-CoV-2 infection, but patients were often asked about this symptom after their diagnosis. This study assessed associations between prospectively reported anosmia and other symptoms related to SARS-CoV-2 infection, and SARS-CoV-2 positivity in community testing centres in Toronto, Ontario.Methods: We conducted a retrospective cross-sectional study in which data were collected from 2 COVID-19 assessment centres affiliated with 2 hospitals in Toronto, Ontario, from Apr. 5 to Sept. 30, 2020. We included symptomatic profiles of all people who underwent a SARS-CoV-2 test at either clinic within the study period. We used generalized estimating equations to account for repeat visits and to assess associations between anosmia and other symptoms and SARS-CoV-2 positivity.Results: A total of 83 443 SARS-CoV-2 tests were conducted across the 2 sites for 72 692 participants during the study period. Of all tests, 1640 (2.0%) were positive; 837 (51.0%) of people who tested positive were asymptomatic. The adjusted odds ratio for the association between anosmia and test positivity was 5.29 (95% confidence interval [CI] 4.50–6.22), with sensitivity of 0.138 (95% CI 0.121–0.154), specificity of 0.980 (95% CI 0.979–0.981), a positive predictive value of 0.120 (95% CI 0.106–0.135) and a negative predictive value of 0.983 (95% CI 0.982–0.984).Interpretation: Anosmia had high specificity and a positive predictive value of 12% for SARS-CoV-2 infection in this community population with low prevalence of SARS-CoV-2 positivity. The presence of anosmia should increase clinical suspicion of SARS-CoV-2 infection, and our findings suggest that people presenting with this symptom should be tested.