Emergency Department Visits With an Influenza Test Ordered or Provided: United States, 2013-2022

Influenza, also known as flu, is a viral respiratory infection. In the 2022-2023 flu season, an estimated 31 million people developed influenza, 360,000 were hospitalized with influenza, and 21,000 died from influenza. To prevent more serious illness, early identification and treatment of influenza is important. This report uses data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) to study trends in the use of influenza testing at hospital emergency department (ED)visits from 2013 through 2022.

Data in this report are from NHAMCS, a nationally representative annual survey of nonfederal general and short-stay hospitals. Results are presented from 2013 to 2022. Estimates and their corresponding variances were calculated using SAS-callable SUDAAN software. Differences between percentages were evaluated using two-sided significance  t  tests at the 0.05 level. Linear regression was used to test the significance of slope.

ED visits by children ages 0-5 years had the highest percentage of influenza tests ordered or provided in 2013 and 2022. Percentages of ED visits with an influenza test ordered or provided increased between 2013 and 2022 for all age groups. Fever and cough were the most frequent first-listed reasons for ED visits at which an influenza test was ordered or provided in both 2013 and 2022. Percentages of ED visits with an influenza test ordered or provided increased within each region of the United States (Northeast, Midwest, South, and West) between 2013 and 2022.