| ObjectiveEvaluate the feasibility of gold immunochromatographic assay (GICA) for early screening for influenza.And investigate influenza infection and antibody levels of some hospitalized patients in the Department of Respiration.MethodsDistricting from September 16, 2009 to February 1, 2011, GICA was utilized to detect the FluA antigen in the oral pharynx secretion for 1193 patients in the Department of Respiration of the General Hospital of Beijing Military. 399 serum samples were collected during the period ,in which there were 115 paired serum samples. The serum samples were centrifuged in EP tubes, and then they were transferred to 4℃for reservation within 24 hours at -20℃. The frozen paired serum samples were sent to the laboratory in Beijing Disease Prevention and Control Center (CDC) at 4℃in different batches, and the hemagglutination inhibition assay (HI) was carried out to detect three kinds of subtypes of HIAb of FluA ( the novel H1N1, H1N1 and H3N2). And evaluate GICA according to the paired serum HI antibody method as "gold standard method",and meanwhile investigate influenza infection and antibody levels in some hospitalized patients in the Department of Respiration.Results1.The nasal pharynx swab samples were subjected to rapid detection on FluA by using GICA ,49 cases were positive and the positive rate was 4.1%(49/1193),and the time of detection were mainly between September and December in 2009.Confirmed cases of FluA by HI were 22 cases,FluA (the novel H1N1) detection rate was 4.3% (5/115),and FluA(H1N1) detection rate was 2.6%(3/115),and FluA(H3N2) detection rate was 6.1%(7/115),and FluA mixed infection rate was 6.1%(7/115).And FluA (novel H1N1) detection time was mainly in Octobetor to December 2009. And then it exisited as mixed infection with FluA (H3N2 and H1N1).2. Among the positive results using HI,the patients with pneumonia and chronic pulmonary heart disease accounted for 18/22,and there were 9 cases of severe pneumonia;the elders accounted for 15/22.The patients with 4 times increase in antibody titers who only had the original lung disease aggravating accounted for 10/22, and the number of temperature≥38℃was 12 cases. The patients with 2 fold increase in antibody titers who only had the original lung disease aggravating accounted for 10/23, and the number of temperature≥38℃was 13 cases.3.The comparison in the detection rate of the antibody which was≥1:40 titer, in three kinds of FluA subtypes showed that the detection rate on the FluA ( H3N2) was 46.1%,FluA(H1N1) was 32.2%,FluA (the novel H1N1)was 20.9%,and the difference was statistically significant (χ~2=16.586,P﹤0.001).Compared HIAb titer≥1:40 detection rate of FluA (the novel H1N1) with that of FluA (H3N2),χ~2 =16.419, P <0.001, the difference was statistically significant.The comparison in the HIAb titer≥1:40 detection rate on novel FluA (H1N1) in the groups of two ages showed that it was relatively high in patients lower than 65, and the difference with the group of not lower than 65 was statistically significant (χ~2=7.938, P=0.002).When the elder group in the antibody titer≥1:40′share was compared, the difference was statistically significant (χ~2=12.669, P = 0.002).4.Consistency checking was carried out on the results from GICA and HI, and Kappa value was 0.682 ,and the P value in the pairedχ~2 test was higher than 0.05, and the difference was not statistically significant.The sensitivity of GICA was 68.2%,and the specificity was 93.5%,and the area under the ROC curve was 0.809,and the coincidence was 84.3%,and misdiagnosis rate was 6.5%,and omission diagnose rate was 31.8%,and Youden index was 0.617.Conclusion1.Compared with HI,the sensitivity for FluA antigen detection by using GICA is relatively low,and the specificity is relatively satisfactory,and the consistency of these two kinds of methods were relatively good. Thus GICA has certain values in the clinical screening for FluA infection.2. In the present study, the confirmed cases from the HI detection were mostly found in the group of pneumonia(particularly severe pneumonia) and chronic cor pulmonale patients. We should pay attention to not only influenza-like illness, but also the original symptoms of lung disease which may be one of manifestations of influenza infection.3. Among the detection rate convalescent serum HIAb titer≥1:40, the highest was FluA (H3N2),and it also failed to meet the crowd of a strong immunity level.The comparison in the HIAb titer≥1:40 antibody detection rate on FluA (the novel H1N1) in the groups of different ages showed that it was relatively low in patients higher than 65, and thus it was still required to inoculate the seasonal trivalent vaccine for FluA as schedule,especially in the patients with pulmonary heart disease and other chronic lung disease.4. After 2009 influenza A( the novel H1N1) pandemic, influenza A(the novel H1N1) forms a mixed infection with the seasonal distribution of influenza . WHO is initially expected to verify the 2009 H1N1 influenza virus in the next few years following the way that the virus continues to spread as seasonal trends. And diverging and spreading of seasonal FluA are not neglectable.
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