This is a summary, written by members of the CITF Secretariat, of:

Moura CS, Morrison LJ, Hohl CM, Grant L, Pilote L, Neville A, Hau JP, Bernatsky S, and the Canadian COVID‑19 Emergency Department Rapid Response Network (CCEDRRN) investigators, for the Network of Canadian Emergency Researchers & the Canadian Critical Care Trials Group. Administrative data ICD‑10 diagnostic codes identifies most lab‑confirmed SARS‑CoV‑2 admissions but misses many discharged from the Emergency Department. Sci Rep. 2024 March 12. doi:

The results and/or conclusions contained in the article do not necessarily reflect the views of all CITF members.

A CITF-supported study, published in Scientific Reports, aimed to assess the operating characteristics of the International Classification of Diseases Revision 10 (ICD-10) code introduced by the World Health Organization in 2020. The study found that the ICD-10 diagnostic code U07.1 (used to specify a confirmed medical diagnosis of COVID-19) identified most lab-confirmed SARS-CoV-2 infections in hospital-admitted patients but missed a significant number of cases among those who had been discharged. This study was led by Dr. Sasha Bernatsky (McGill University), and Dr. Corinne Hohl (University of British Columbia) as part of the Canadian Network for Advanced Interdisciplinary Methods for comparative effectiveness research team ( CANAIM was initially funded by the Drug Safety and Effectiveness Network (DSEN), a collaboration between the Canadian Institutes of Health Research and Health Canada.

The ICD-10 codes were assessed using the Canadian COVID-19 Emergency Department Rapid Response Network (CCDERN) registry. CCDERN collected data from hospital or emergency departments (EDs) very early in the pandemic when at-home testing was not widely available. Participant data were drawn from 51 urban and rural EDs across eight Canadian provinces from March 2020 to August 2021. Analysis was stratified by whether the ED visit (n=77,000) resulted in a discharge (n=31,430) or in being admitted to hospital (n=45,570).

Key findings:

  • The sensitivity of code U07.1 for a positive SARS-CoV-2 test was 93.6% in patients admitted to hospital and 83% in those discharged from the ED.
  • Additional parameters, such as specificity, positive predictive value (PPV), and negative predictive value (NPV) were always better for those admitted to hospital compared to those who were discharged:
    • For hospitalized versus discharged patients, specificity was 99.8% and 97.5%, respectively.
    • For hospitalized versus discharged patients, PPV was 98.6% and 90.1%, respectively.
    • For hospitalized versus discharged patients, NPV was 98.8% and 95.5%, respectively.

Thus, ICD-10 code U07.1 had only moderate agreement with PCR test positivity in patients discharged from the ED. This limitation is important to acknowledge if administrative data from ED discharges using this code are to be used for health policy decisions, including resource planning.