We found that the sensitivities of 3 rapid influenza antigen tests for pandemic influenza A/H1N1 virus were low to moderate: BD Directigen EZ Flu A+B test (Becton Dickinson), 46.7%; BinaxNOW Influenza A&B (Inverness Medical), 38.3%; and QuickVue Influenza A+B Test (Quidel), 53.3%. A patient with influenza-like illness who has a negative rapid antigen test result should undergo further testing using reverse-transcription polymerase chain reaction.