目的 了解丙型肝炎核心抗原(HCV-cAg)检测方法的敏感性及特异性,确定具有临床意义的S/CO值,探讨其在丙型肝炎诊断中的意义.方法 使用ELASA方法检测丙型肝炎核心抗原,RT-PCR检测HCV RNA定量,观察不同S/CO值所对应的HCV RNA定量之间的关系,以HCV RNA为诊断金标准,列四格表做诊断实验.结果 HCV-cAg抗原检测的敏感性为87.05％,特异性为76.67％,阳性预测值为96.53％,阴性预测值为44.23％.结论 (1)随着HCV-cAg的S/CO值逐渐增大,其与HCV RNA阳性符合率明显增高,随着HCV-cAg的S/CO值减小,其与HCV RNA阴性符合率明显增高；(2)S/CO值=2可以作为临床判断HCV感染病毒血症存在的一个标准；(3)本实验的敏感性和特异性较好,检测方法简单,可以作为丙型肝炎临床诊断的补充试验及筛查.%Objective To compare the abilities of the hepatitis C virus (HCV) core antigen (cAg) test and the HCV RNA assay for confirming anti - HCV presence in order to determine the clinical utility of the HCV - cAg as an alternative or confirmatory diagnostic tool. Methods Serum samples collected from 158 patients diagnosed with HCV infection were subjected to the enzyme - linked immunosorbent assay - based HCV — cAg test. The optical density ( OD) measured values were used to calculate the ratio of specimen absorbance to the cutoff value (S/ CO). Simultaneously, the serum samples were subjected to PCR - based nucleic acid amplification quantitative fluorescence detection of HCV RNA. Results None of the serum samples had a S/CO value < 1 for the HCV - cAg test (100% negative) , but all of the samples had a S/ CO value >5 ( 100% positive). The HCV - cAg test sensitivity was 87. 05% , specificity was 76. 67% , positive predictive value was 96. 53% , and negative predictive value was 44. 23% . As the S/CO value gradually increased, the significantly higher positive coincident rate of the HCV RNA test decreased. The HCV RNA negative coincident rate was significantly higher than that of the HCV - cAg test. HCV - cAg S/CO values between 1 and 2 corresponded to an HCV RNA values between 1. 0 x 103 copies/ml and 1. 0 x 104 copies/ml. The highest S/CO value obtained was 1. 992. Conclusion The HCV - cAg test is comparable to the HCV RNA assay for diagnosing HCV infection.
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