e Rapid and definitive diagnosis of viral respiratory infections is imperative in patient triage and management. We compared the outcomes for adult patients with positive tests for respiratory viruses at a tertiary care center across two consecutive influenza seasons (winters of 2010-2011 and 2012). Infections were diagnosed by conventional methods in the first season and by multiplex PCR (FilmArray) in the second season. FilmArray decreased the time to diagnosis of influenza compared to conventional methods (median turnaround times of 1.7 h versus 7.7 h, respectively; P ؍ 0.015); FilmArray also decreased the time to diagnosis of non-influenza viruses (1.5 h versus 13.5 h, respectively; P < 0.0001). Multivariate logistic regression found that a diagnosis of influenza by FilmArray was associated with significantly lower odds ratios (ORs) for admission (P ؍ 0.046), length of stay (P ؍ 0.040), duration of antimicrobial use (P ؍ 0.032), and number of chest radiographs (P ؍ 0.005), when controlling for potential confounders. We conclude that the rapid turnaround time, multiplex nature of the test (allowing simultaneous detection of an array of viruses), and superior sensitivity of FilmArray may improve the evaluation and management of patients suspected of having respiratory virus infections. R espiratory viruses can cause not only mild upper respiratory tract infections but severe pneumonia, especially in immunocompromised hosts. Rapid and definitive diagnosis is critical in the management of viral respiratory infections and in timely isolation of infected patients. The 2009 H1N1 pandemic revealed the need for better diagnostic tests for influenza viruses. In addition, overlapping clinical presentations impede clinicians' ability to predict causative pathogens (whether bacterial or viral) and may lead to unnecessary antimicrobial use (1, 2). Nucleic acid amplification testing (NAAT)-based methods for detection of viral pathogens are increasingly used due to their excellent sensitivity and specificity and their ability to detect a wide spectrum of viral agents. Therefore, NAAT has many potential advantages over traditional methods, such as rapid antigen testing (which is Ͻ40 to 60% sensitive for influenza in adults), direct fluorescent-antibody (DFA) testing (which requires specialized laboratory training), or viral culture (which can take up to 10 days for a result) (3). Multiplex PCR using FilmArray (BioFire Diagnostics, Inc., a bioMérieux company, Salt Lake City, UT) is an NAAT method which can detect multiple viral pathogens with a single test (4). The FilmArray respiratory viral panel (RVP) was FDA cleared in May 2011 to detect 15 respiratory viral pathogens: influenza A virus and subtypes (influenza A H1, influenza A H1 2009, and influenza A H3 viruses), influenza B virus, parainfluenza 1 virus, parainfluenza 2 virus, parainfluenza 3 virus, parainfluenza 4 virus, respiratory syncytial virus (RSV), human metapneumovirus, adenovirus, rhinovirus/enterovirus, coronavirus NL63, and coronavirus HKU1.In Febr...