Comparison of the Denka-Seiken INFLU A.B-Quick and BD Directigen Flu A+B kits with direct fluorescent-antibody staining and shell vial culture methods for rapid detection of influenza viruses.

The INFLU A.B-Quick and Directigen Flu A+B enzyme immunoassays were compared with direct immunofluorescence and cell culture for detection of influenza A and B viruses in a total of 255 patient specimens. Both assays identified 23 of 42 influenza A viruses (sensitivity, 54.8%; specificity, 100%; positive predictive value [PPV], 100%; negative predictive value [NPV], 91.8%). The INFLU A.B-Quick assay identified 10 of 16 influenza B viruses (sensitivity, 62.5%; specificity, 99.6%; PPV, 90.9%; NPV, 97.5%), and the Directigen Flu A+B assay detected 9 of 16 influenza B viruses (sensitivity, 56.3%; specificity, 99.6%; PPV, 90%; NPV, 97.1%).