One rapid membrane chromatography test and 2 immunofluorescence tests were compared with polymerase chain reaction as tools for the diagnosis of influenza in 277 patients treated in an emergency department. The sensitivity on days 1-3 of symptoms was 71% for the rapid membrane chromatography test, 70% for the first immunofluorescence test, and 79% for the second immunofluorescence test. Rapid tests are useful for round-the-clock identification of influenza, with follow-up polymerase chain reaction used for confirmation.
