Analytical sensitivity of rapid influenza antigen detection tests for swine-origin influenza virus (H1N1).

BACKGROUND A novel swine origin influenza virus (S-OIV) (H1N1) is spreading worldwide and threatens to become pandemic. OBJECTIVES Determine analytical sensitivity of selected commercially available rapid influenza antigen detection tests in detecting S-OIV H1N1. STUDY DESIGN Serial dilutions of two S-OIV isolates, one seasonal influenza A (H1N1) isolate and a nasopharyngeal aspirate from a patient with S-OIV disease were tested in five commercially available influenza antigen detection tests and by virus isolation in cell culture. Viral M gene copy number was determined by quantitative PCR methods. RESULTS The analytical sensitivity of the five influenza antigen detection tests for S-OIV (tissue culture infectious dose 50 (TCID(50)) log(10)3.3-4.7 was comparable with that of seasonal influenza (TCID(50) log(10)4.0-4.5). CONCLUSION The analytical sensitivity of the selected influenza A antigen detection tests for detection of S-IOV was comparable with that of seasonal influenza H1N1.