静脉吸毒人群抗-HCV及HCV RNA检测临床应用探讨

Application of anti-HCV and HCV RNA detection in intravenous drug users

目的探讨抗-HCV及HCV RNA检测在静脉吸毒人群中HCV感染的诊断价值,为静脉吸毒人群HCV感染诊断提供一种准确、高效的检测策略。方法收集527例静脉吸毒者的血浆样本,先进行抗-HCV筛查试验(ELISA),对结果呈反应性样本用重组免疫印迹试验(RIBA)进行抗体确证;并对所有样本进行HCV RNA检测,然后分析抗-HCV筛查试验、RIBA及HCV RNA检测(NAT)结果。对数据进行统计描述。结果527例静脉吸毒者样本的抗-HCV ELISA结果中有386例呈反应性,141例为抗-HCV阴性;经RIBA检测386例抗体反应性样本中有370例抗-HCV阳性、6例抗-HCV不确定和10例抗-HCV阴性。抗-HCV ELISA与RIBA检测阳性符合率为95.85%(370/386),静脉吸毒人群中抗-HCV阳性率为70.21%(370/527)。10例抗-HCV RIBA阴性样本经HCV RNA检测,均为阴性。376例抗-HCV RIBA阳性和不确定样本经HCV RNA检测,有56.93%(300/527)为HCV现症感染,14.42%(76/527)为HCV既往感染。对141例抗-HCV ELISA结果呈阴性的样本进行HCV RNA检测,抗-HCV ELISA筛查残余风险度为1.52%(8/527)。静脉吸毒人群中HCV病毒载量分布显示,高载量值(>10^(7)IU/ml)和低载量值(<10^(2)IU/ml)分别占1.95%和2.27%,而载量值在1×10^(2)~1×10^(7)IU/ml的样本占95.78%(295/308),且主要分布于1×10^(5)~1×10^(6)IU/ml(37.99%)。"ELISA+RIBA+NAT"的检测策略能区分300例HCV现症感染、76例HCV既往感染及10例抗-HCV假阳性结果,而"ELISA+NAT"检测策略能检测出300例HCV现症感染者,但不能区分出386例抗体筛查阳性者中存在的10例抗体筛查假阳性(2.59%)。结论静脉吸毒人群是HCV感染的高危人群,有很高的现症感染率,这些HCV感染者体内病毒载量值均维持在较高水平。对静脉吸毒人群抗-HCV筛查将有一定的残余风险度,因此,对静脉吸毒人群用抗-HCV ELISA筛查加核酸检测策略能准确诊断现症感染者,但不能区分出抗体筛查假阳性。

Objective To explore the diagnostic value of anti-HCV and HCV RNA so as to provide an accurate and efficient detection strategy for the diagnosis of HCV in intravenous drug users.Methods 527 plasma samples from intravenous drug users were collected,and preliminary anti-HCV ELISA screening test was performed.A recombinant immunoblot assay(RIBA)was used as confirmatory assay for reactive antibody samples.All samples were tested for HCV RNA,followed by analysis of anti-HCV screening test,RIBA and HCV nucleic acid test results.Results Anti-HCV ELISA results were reactive in 386 out of 527 intravenous drug users and non-reactive in 141.Among the 386 reactive antibody samples detected by RIBA,370 cases were anti-HCV positive,6 cases were anti-HCV indeterminate and 10 cases were anti-HCV negative.Anti-HCV ELISA and RIBA positive coincidence detection rate was 95.85%(370/386),and 70.21%(370/527)among intravenous drug users.HCV RNA was negative in all 10 anti-HCV RIBA non-reactive samples.376 anti-HCV RIBA-positive and indeterminate samples were tested for HCV RNA,of which 56.93%(300/527)were current HCV infection,and 14.42%(76/527)were past HCV infection.Among 141 anti-HCV ELISA negative samples,the residual risk by anti-HCV ELISA screening for HCV RNA was 1.52%(8/527).HCV viral load distribution among intravenous drug users showed that the high viral load value(>10^(7)IU/ml)and low viral load values(<10^(2)IU/ml)accounted for 1.95%and 2.27%,respectively,while the samples with viral load value of 1×10^(2)~1×10^(7)IU/mL accounted for 95.78%(295/308),and were mainly distributed in 1×10^(5)~1×10^(6)IU/ml(37.99%).ELISA+RIBA+NAT assay detection strategies had differentiated 300 cases of current HCV infection,76 cases of past HCV infection and 10 cases of false positive anti-HCV results,while ELISA+NAT assay detection strategies had only detected 300 cases of current HCV infection.However,of the 386 positive subjects screened for antibodies,10(2.59%)were undifferentiated false positives.Conclusion Intravenous drug users are the high-risk population of HCV infection with high prevalence and high viral load.Anti-HCV screening for intravenous drug users will have a certain degree of residual risk.Therefore,anti-HCV ELISA screening and nucleic acid detection strategy can accurately diagnose the current infected patients;however,it cannot distinguish the false positive results of antibody screening.