Evaluation Of Nucleic Acid Testing Strategies For Hepatitis C Clinical Diagnosis

BackgroundHepatitis C virus(HCV) is mainly transmitted by blood, which leads to Hepatitis C through out the world. Due to its hidden infection and atypia symptoms, the clinical diagnosis of Heptaitis C mainly relies on the laboratory testing results. Anti-HCV specific antibody is one of the key indicators in Hepatitis C clinical diagnosis. Testing for anti-HCV should include the use of antibody screening assay, for screening test-positive results, a more specific supplemental assay. Initial screening and verifying the presence of anti-HCV antibody general use enzyme immunoassays (EIA) and recombinant immunoblot assay (RIBA). Verifying the presence of anti-HCV minimizes unnecessary medical visits and psychological harm for persons who test falsely positive by screening assays and ensures that counseling, medical referral, and evaluation are targeted for patients who are serologically confirmed as having been infected with HCV. Thus screening and supplemental tests should be used together as a testing strategy so as to provide more reliable results for clinical diagnosis. HCV related tests have been extensively developed in clinical laboratories in China. But there are still no clear detection strategies and corresponding results explanation. China CDC was entrusted by Health and Family Planning Commission to issue the "Technical Specification for Hepatitis C Virus Laboratory Tests", which details the HCV clinical diagnosis strategy requirements, puts forward the clinical diagnosis HCV antibody screening strategy, HCV clinical diagnosis nucleic acid testing strategy, etc. Nucleic acid testing strategy for HCV clinical diagnosis is to confirm HCV antibody screening positive samples using Nucleic Acid Test (NAT) and RIBA combined detection. A rigorous assessment should be performed to determine the availability, accuracy, reliability. This research mainly focuses on the HCV nucleic acid testing strategy for clinical diagnosis, since the HCV antibody screening strategy has been evaluated.Objective1. To evaluate the performance of HCV nucleic acid detection assay for the follow-up HCV clinical diagnosis of nucleic acid testing strategy.2.To evaluate the HCV clinical diagnosis of nucleic acid detection strategy using small sample in the national AIDS reference laboratory scope.3.To evaluate HCV clinical diagnosis of nucleic acid testing strategy in multiple pilot, to provide a strategy that is reasonable and reliable extendable.4. The aim of this research is to lay the foundation for the third stage national evaluation of HCV clinical diagnostic testing strategy, provide more information for further alterations to the "Guideline" in HCV detection strategy, for standardizing the clinical diagnosis of Hepatitis C laboratory testing application in ChinaMethods1. Methodological evaluation. A total of six panels were established (Basic sera panel of HCV nucleic acid detection, HCV subtypes performance panel, HCV RNA linearity performance panel, HCV RNA precision panel and Interfere panel). Blind test were performed on these6panels using domestic HCV nucleic acid detection reagent. The positive coincidence rate, negative coincidence rate, subtype detection ability, linearity, analytical sensitivity, analytical specificity, precision were calculated to evaluate the overall performance of the method.2. Nucleic acid testing strategy for clinical diagnosis evaluation. The study included two stages. The first stage:a blood panel which contains samples with clear infection statues were established for HCV nucleic acid testing strategies assessment within the scope of the national AIDS reference laboratory (NARL). The second stage, Beijing, Tianjin were chosen as pilot sites for evaluating the performance of the nucleic acid testing strategy. Samples for the evaluation were collected from2013HCV/HIV monitoring sentinel drug users and Hepatitis C epidemiological investigation of Beijing hemodialysis population. The sensitivity, specificity, positive predictive value and negative predictive value were calculated for both the assessment phase. ELISA combined with RIBA were used as golden standard. Then, the efficacy of the testing strategy was assessed in populations of different HCV prevalence and different testing sites.Results1. The positive agreement ratio of the HCV RNA detection reagent was49/50(98%); the negative agreement ratio was50/50(100%); the total coincidence rate was99/100(99%). HCV RNA detection reagent performed on interference panel which contained samples that might possibly interfere the HCV RNA test showed an analytical specificity of100%. HCV Type1to6with a total of9subtypes were detected by HCV RNA testing reagent successfully. Precision of domestic HCV nucleic acid detection reagent on high, medium and low HCV RNA concentration samples (102,104,106IU/mL) showed CV less than6%except for panel member with low HCV RNA concentration. CV inter-runs were9.28%,5.03%and9.28%, respectively; the total CV were11.55%,4.45%and3.08%, respectively. A linear correlation coefficient of Domestic HCV nucleic acid detection reagent and Roche COBAS AmpliPrep/COBAS TaqMan HCV test0.9335.2. The sensitivity, specificity, positive predictive value, negative predictive value applied in NARL and polite were all100%. The detection performance of the HCV clinical diagnosis nucleic acid detection strategy showed no significant deference between application in drug users and hemodialysis population (P<0.05). The overall detection performance of the Strategy application has a strong consistency between in NARL and in pilot sites.Conclusionl.The domestic HCV RNA detection kit and Roche COBAS AmpliPrep/COBAS TaqMan HCV positive Test has a high positive coincidence rate, negative coincidence rate, precision and analytical sensitivity. Both of the domestic HCV RNA detection kit and Roche COBAS AmpliPrep/COBAS TaqMan HCV have the ablity of detecting different HCV subtypes. So HCV RNA detection reagents are suitable for the HCV clinical diagnosis of nucleic acid testing strategy evaluation.2. The difference of detection efficacy in people with different infection rate is not significant. Our research illustrated that the efficacy of HCV nucleic acid testing strategy is good for clinical diagnosis with general applicability in both NARL and pilot sites as well as in people with different HCV prevalence, which effectively reduces the false positive rate of detection and testing cost.