Diagnostic Yield of Screening for SARS-CoV-2 among Patients Admitted for Alternate Diagnoses

Phil Davis, Rhonda J. Rosychuk, Jeffrey P Hau, Ivy Cheng, Andrew D. McRae, Raoul Daoust, Eddy Lang, Joel Turner, Jaspreet Khangura, Patrick T. Fok, Maja Stachura, Baljeet Brar, Corinne Hohl


Objectives To determine the diagnostic yield of screening patients for SARS-CoV-2 who were admitted with a diagnosis unrelated to COVID-19, and identify risk factors for positive tests.

Design Cohort from the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN) registry

Setting 30 acute care hospitals across Canada

Participants Patients hospitalized for non-COVID-19 related diagnoses who were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between March 1, and December 29, 2020

Main outcome Positive nucleic acid amplification test (NAAT) for SARS-CoV-2

Outcome measure Diagnostic yield

Results We enrolled 15,690 consecutive eligible adults who were admitted to hospital without clinically suspected COVID-19. Among these patients, 122 tested positive for COVID-19, resulting in a diagnostic yield of 0.8% (95% CI 0.64% – 0.92%). Factors associated with a positive test included presence of a fever, being a healthcare worker, having a positive household contact or institutional exposure, and living in an area with higher 7-day average incident COVID-19 cases.

Conclusions Universal screening of hospitalized patients for COVID-19 across two pandemic waves had a low diagnostic yield and should be informed by individual-level risk assessment in addition to regional COVID-19 prevalence.

Link: MedRxiv