A National Study of the Impact of Rapid Influenza Testing on Clinical Care in the Emergency Department.

BACKGROUND Rapid influenza diagnostic tests (RIDT) may influence physician decision-making. Single-center studies suggest that influenza diagnosed in association with RIDT reduces ancillary testing and antibiotic prescribing. The extent of RIDT use in US emergency departments (EDs) and their impact on patient management are unknown. We examined the use of RIDT and its effect on influenza management, using a national sample of ED visits. METHODS We performed a retrospective study using data from the National Hospital Ambulatory Medical Care Survey, an annually administered survey capturing a nationally representative sample of visits to US EDs. We identified patient visits in which RIDT was performed and/or influenza was diagnosed across 3 influenza seasons (2007-2009). Ancillary testing and antibiotic and antiviral prescribing were evaluated for 2 groups of patients in whom RIDT was performed (those given or not given a diagnosis of influenza) and a third group in whom influenza was diagnosed but RIDT was not performed. RESULTS Rapid influenza diagnostic tests were performed during 4.2 million visits. Forty-two percent of influenza diagnoses were made in association with RIDT. For patients diagnosed with influenza, ancillary test ordering was lower (45% vs 53% of visits) and there were fewer antibiotic prescriptions (11% vs 23%), and antiviral use was higher (56% vs 19%) when the diagnosis was made in association with RIDT. CONCLUSIONS Influenza diagnoses made in association with RIDT resulted in fewer tests and antibiotic prescriptions and more frequent use of antivirals. This finding suggests that test results influence physician behavior.