NS1抗原在广州市登革热检测中的应用评价

Evaluation of NS1 antigen in detection of dengue fever in Guangzhou

目的初步评价NS1抗原检测在广州市登革热高发季节中的应用价值及影响因素。方法选取2017年6-11月登革热确诊病例454例及相应的对照样本648例。同时采用酶联免疫吸附试验(ELISA)检测NS1抗原、IgM及IgG抗体,实时荧光定量聚合酶链反应(RT-PCR)检测病毒RNA。采用χ~2检验对结果进行分析。结果 NS1-ELISA检测的灵敏度和特异度分别为94.27%和94.59%,阳性似然比和阴性似然比分别为17.46和0.06,Kappa值为0.88;NS1-ELISA法与IgM/IgG-ELISA法联合使用能明显提高检测灵敏度(χ~2=8.588,P<0.01),但检测的特异度降低(χ~2=9.360,P<0.01);NS1-ELISA法对于早期病人检测的灵敏度明显高于IgM/IgG-ELISA法(χ~2=155.529,P<0.001);登革病人中IgG抗体的出现会降低NS1抗原检出率(χ~2=33.522,P<0.001)。结论 NS1-ELISA检测在广州市登革热早期病例的检测中具有较高的灵敏度,与其它方法联合使用能有效地提高检测灵敏度,但是抗体的出现会降低NS1抗原检出率。

Objective To evaluate the value of NS1 antigen assay in the high season of dengue fever in Guangzhou and the factors influencing the assay. Methods 454 confirmed cases of dengue fever and 648 corresponding control samples from June to November in 2017 were collected. NS1 antigen and IgM antibody were detected by enzyme linked immunosorbent assay （ELISA） and DENV RNA were detected by real time fluorescent quantitative PCR （RT-PCR）. Results were analyzed by the Chi square （X2） test. Results The sensitivity and specificity of NS1-ELISA assay were 94.27% and 94.59% , respectively. The positive likelihood ratio （PLR） and negative likelihood ratio （NLR） were 17.46 and 0.06, respectively, The Kappa value was 0.88. Combined NS1-ELISA and other methods increased the sensitivity of detection （X2=8.588, P〈 0.01） , but the specificity was reduced （X2=9.360, P〈0.01 ）. For early patient testing, the sensitivity of NS1-ELISA was significantly higher than IgM/IgG-ELISA （X2=155.529, P〈0.001 ）. The presence of IgG antibodies reduced the detection rate of NS1 antigen （X2=33.522, P〈0.001）. Conclusion NS1-ELISA has high sensitivity in screening early dengue fever in Guangzhou. Combined use of NS1-ELISA and other methods can effectively increase the sensitivity of detection. However, the presence of antibodies reduces the detection rate of NS1 antigen.