Detection Rate of Rapid Antigen Test for Pandemic Influenza A (H1N1 2009)

There are few datas on the diagnostic accuracy of rapid antigen test for pandemic influenza A (H1N1). We evaluated the performance of rapid antigen test for the diagnosis of pandemic influenza A (H1N1). During the period from 21 August 2009 to 20 September 2009, 451 patients with influenza-like symptom underwent the rapid antigen test (SD Influenza Antigen, Standard Diagnostics, Yongin, Korea) and real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) at the same time. Rapid antigen test results were positive for 65 of 90 patients with the positive results for pandemic influenza A (H1N1) on rRT-PCR assay. The sensitivity of the rapid antigen test was 72.2% (95% CI, 61.8-81.1) and the specificity was 100% (95% CI, 99.0-100). The positive predictive value was 100% (95% CI, 94.5-100) and negative predictive value was 93.5% (95% CI, 90.6-95.8).