For patients with clinical concern for influenza, the usual workflow in the BMC ED is that physicians order the collection of a nasopharyngeal swab (NPS) for influenza A/B testing to be performed in the core microbiology laboratory using one of two assays. The two influenza A/B-only assays available in the core lab are a) an instrumented fluorescent immunoassay rapid antigen test, the Sofia influenza A+B FIA (Quidel Corporation) and b) an automated real-time PCR test, the Xpert Flu (Cepheid, Inc.). Which test is ordered is at the discretion of the physician. Both the Sofia and Xpert assays provide a result callout to distinguish influenza type A from type B.

Prior to the study the Cobas Liat Influenza A/B assay will be verified for patient care at BMC. The instrument and test kits will be available in the ED for use with study subjects randomized to this study arm. The Cobas Liat assay provides a result callout to distinguish influenza type A from type B.

For patients randomized to the Core Lab Testing Arm, ED physicians will order an influenza test to be performed in the core lab.

The time elapsed from when a patient was placed in the ED treatment room until the disposition (either admit, observe, or discharge) was ordered in the medical record

Whether patients either received a dose of antibiotics in the ED or received a prescription for antibiotics on discharge from the eD