Application of the fluorescent immunoassay kit for influenza virus antigen detection in influenza screening

Objective To explore the clinical application value of fluorescent immunoassay kit for influenza virus antigen detection by comparing the method to the direct fluorescent antibody staining and the reverse transcriptase polymerase chain reaction (RT-PCR) of influenza virus nucleic acids. Methods From July to December 2017, 350 patients in the fever clinic were examined by the fluorescent immunoassay kit for influenza virus antigen detection (Sofia FIA), direct fluorescent antibody staining (DFA) and RT-PCR of influenza virus nucleic acids. Results A total of 186 cases of influenza A/B viruses were detected by Sofia FIA, with an overall positive detection rate of 53.1%, and the detection rates of influenza A and B viruses were 35.4% and 17.7%, respectively. Compared to RT-PCR, the results of sensitivity, specificity, positive predictive value, negative predictive value, consistency rate and kappa value of Sofia FIA were 89.4%, 100.0%, 100.0%, 86.6%, 93.7% and 0.873 in the combined detection of influenza A/B viruses; 87.9%, 100.0%, 100.0%, 92.5%, 95.1% and 0.897 in the detection of influenza A virus; and were 92.5%, 100.0%, 100.0%, 98.3%, 98.6% and 0.952 in the detection of influenza B virus, respectively. Compared to RT-PCR, the results of sensitivity, specificity, positive predictive value, negative predictive value, consistency rate and kappa value of DFA were 83.2%, 100.0%,100.0%, 80.2%, 90.0% and 0.800 in the combined detection of influenza A/B viruses; 82.3%, 100.0%, 100.0%, 89.3%, 92.9% and 0.847 in the detection of influenza A virus; and were 85.1%, 100.0%, 100.0%, 96.6%, 97.1% and 0.902 in the detection of influenza B virus, respectively. Conclusions Sofia FIA and DFA had high sensitivity and specificity, and were in consistency with RT-PCR. The methods showed have certain clinical significance in the screening of influenza. Key words: Influenza; Rapid detection of influenza virus; Fluorescent immunoassay; Diagnosis