The Blood Screening Strategy Of Hepatitis C Virus

The number of HCV infection, about40million, of which about50percent carry the virus,is the highest in the world. Transfusion-transmitted is still an important route of HCV infection.The analysis of blood donors in the epidemiological characteristics and the development ofHCV blood screening strategy is the most effective role of blocking the transfusion-transmitted.HCV screening techniques have been developed more mature. Anti-HCV ELISA detectionis the most important and common method in blood screening of HCV infection. It can beeffectively blocked of a blood transfusion spread of HCV. However, a longer window periodcould cause to undetected. Nucleic acid method has a significant detection advantage withwindow period samples, but the expensive cost of testing and the experimental requirementslimit its promotional use. Antigen-antibody Combination assay can detect HCV antibodies andantigens by better sensitivity and specificity. It is a simple, short of detection time, simple of labenvironment, low costs, and is compatible with the current of HCV-Ab EIA blood screeningsystem and so on. The article is intended to explore a cost-effective blood screening strategy byanalyzing the value of HCV antibody reagents, antigen-antibody combination reagent in theblood screening.The first part is the Analysis of voluntary blood donation in Beijing about the HCVinfection and epidemiological investigations. According to5`-UTR conserved sequence primersfor reverse transcription and nested PCR amplification, RNA-positive samples do genotypingsequencing analysis from conventional anti-HCV ELISA detection. Anti-HCV positive rate is0.35%in this survey, in which HCV nucleic acid-positive rate is0.10%, and more than85%arethe first time blood donors; Genotype of Beijing blood donors for HCV infection is still1b and2a-based, respectively,63.56%,20.15%;3a genotype is4.65%;3a/3b mixed genotype is6.98%;3b genotype was0.78%.And the6a/1b is3.88%.The presence of genotype3b show thathigh-risk groups of injecting drug users has become one of the dangerous source oftransfusion-transmitted risk and the further epidemiological investigation is clear for blooddonors characteristics;6a genotype suggest north-south differences getting smaller and smallerin genotype distribution, which may be substantially the increased proportion of floatingpopulation of Beijing in recent years.The second part is the analysis of anti-HCVELISA detection in blood screening. Using three kinds of HCV-ELISA reagents from Ortho WT and Murex detect in parallel for987samples in which674samples for RIBA strip analysis, and851samples for RNA testing. Theresults analysis by ROC curve.The Ortho and the Murex have a better detection for the positiveconfirmation samples, and the WT reagent is lower relatively. It is different significantly of C,NS3, NS5fragment detection results of the three reagents, NS3especially. Blood banks couldtake early re-examination based on a reasonable choice of different anti-HCV reagents on thedetection characteristics of the different segment of HCV antibody reagents. ROC curve analysisshow that the Youden index of a single reagent to confirm specimens was significantly lowerthan the detection of two different reagent combinations. The detection of double-reagent HCVis higher than the single reagent. The42cases of undetected specimens are RNA+/RIBA-orRNA+/RIBA Ind, suggest that it is important factor of the window period for the undetected ofanti-HCVELISA.The third part is the investigation of the application of the Murex HCV Ag/Ab combination(version4.0) assay and combined detection of HCV EIA antibody reagents in blood screening.987HCV-Ab reactive and gray zone samples were collected from routine blood screening anddetected by both the Murex HCV Ag/Ab combination assay and Murex HCV Ab reagent. Andsupplemental retested by RIBA and HCV NAT test. The positive, the negative and the final onesof detected rate of Murex HCV Ag/Ab combination assay and the Murex HCV Ab assay one arestatistically significant. And the positive, the negative and the final ones of compliance ratebetween Murex HCV Ag/Ab combination and Murex Ab assay are statistically significant.Further, Murex HCV Ag/Ab kits are assembled with other reagent (ORTHO,WT) and comparethe rate of missed detection and false positive sample. Analysis of the ROC curve is statisticallysignificant, and the Youden index slightly higher than the combination of antibody reagents.HCV Ab assay For5RIBA negative/RNA positive(including confirmed window periodsample)Among123inconsistent samples, Murex HCV Ag/Ab detected out4samples；MurexHCV Ab detected out only one sample; for15RIBA positive and RNA negative sample,MurexHCV Ag/Ab found5samples and10samples reacted with Murex HCV Ab. The RIBA negativeand RNA positive samples could be detected out by Murex HCV Ag/Ab combination assayefficiently. Because the low compliance rate between Murex HCV Ag/Ab combination andMurex HCV Ab assay, we recommend the conjunction application of Murex HCV Ag/Abcombination and the Murex/Ortho/WT HCV Ab assay in blood screening. The duplicated HCVEIA blood screening strategy, especially the combination of HCV Ag/Ab combinationreagents and antibody reagents, can help to reduce the possibility of transfusion transmittedinfected diseases.The undetected samples and the false-positive samples caused by blood screening detection experiments, show we could not rely on a single HCV blood screening test results todetermine the whereabouts of the blood. The blood testing standards, screening andconfirmation test prevent undetected blood safety hazards, and reduce the damage to the blooddonors by false-positive sample. It is a foundation for assessment of blood donors and repeatdonor choice.