Incidentally Detected SARS-COV-2 Among Hospitalized Patients in Los Angeles County, August to October 2020.

We aimed to determine the percentage of COVID-19- associated hospitalizations reported to Los Angeles County (LAC) Public Health that might have been misclassified because of incidentally detected SARS-CoV-2. We retrospectively reviewed medical records from a randomly selected set of hospital discharges reported to LAC Public Health from August to October 2020 for a clinical diagnosis of COVID-19 or a positive SARS-CoV-2 test result. Among the 13,813 discharges from 85 hospitals reported to LAC Public Health as COVID-19-associated hospitalizations from August to October 2020, 346 were randomly selected and reviewed. SARS-CoV-2 detection was incidental to the reason for hospitalization in 12% (95% confidence limit, 9%-16%) of COVID-19 classified hospital discharges. Adjusting COVID-19-associated hospitalization rates to account for incidental SARS-CoV-2 detection could help public health policymakers and emergency preparedness personnel improve resource planning.