Reliability of a rapid test for the clinical diagnosis of influenza A/H1N1 2009

AbstractBackground: The rapid diagnosis of a pandemic influenza A/H1N1 2009 (H1N1pdm) virus infection is required in ambulatory care settings, since early identification can prevent further transmission. However, the sensitivity of rapid influenza diagnostic tests (RIDTs) is still questionable, and specific indicators for H1N1pdm and/or false-negative results by RIDTs have not been clearly determined.Methods: From June to December 2009, nasal swabs from 324 patients at Kochi Health Science Center were used for the diagnosis of infection by RIDT and reverse transcription polymerase chain reaction. Results: The sensitivity of the RIDT was determined to be 80.0% and the specificity 97.1%. Multivariate analysis revealed that the frequencies of contagiousness and headache were significant in patients with H1N1pdm infection, in addition to common symptoms of respiratory infection. These data indicated that the H1N1pdm virus had high infectivity and was harmful to the endocranial environment. In the false-negati...