[Rapid diagnosis of influenza by detecting viral M protein in an immunoenzyme test]

Previously developed ELISA test system with sensitivity about 0.5 ng/ml of virus protein M was used for influenza virus detection in nasopharyngeal washings of patients with acute respiratory virus diseases (ARVD). Altogether 184 specimens from patients with ARVD and 31 from patients with other infections were examined in the pre-epidemic and epidemic periods of 1983. In parallel, virus antigens were detected by direct immunofluorescence test (IF). The total frequency of viral antigen detection by ELISA and IF coincided (63% of the specimens examined). With the specimens collected early in the disease (2-3 days) the rate of virus findings by ELISA rose to 82%. Direct detection of viral antigen in nasopharyngeal washings by means of an objective immunochemical method seems to be promising for a large-scale rapid diagnosis of influenza.