title: Prediction of viremia for cases of hepatitis C virus (HCV) infection using a third-generation anti-HCV enzyme immunoassay test.
abstract: OBJECTIVE
  Positive results for anti-hepatitis C virus (HCV) testing reveal subjects are infected by HCV, with presence of HCV RNA indicating persistent infection. In this study, we attempted to evaluate the validity of the HCV viremia using a commercially available, third-generation anti-HCV test.
  
  
  METHODS
  Sample rate/cut-off rate (S/CO) ratios for 1,907 anti-HCV-positive tests (S/CO >1, AxSYM HCV 3.0; Abbott, IL, USA), which had been performed during the last three years, were retrospectively analyzed. Cases with S/CO values between 1 and 100 were divided into 20 groups according to S/CO range (in increments of 10) and ALT (normal or elevated). Ten random cases were obtained for each of the 20 groups. If cases in any group numbered < or =10, all were recruited. Totally, 193 cases were enrolled for HCV RNA detection (COBAS Amplicor; Roche Diagnostics, NJ, USA).
  
  
  RESULTS
  The S/CO distribution was biphasic, with two S/CO peaks in the ranges 1-10 (10.7%) and 81-90 (24.2%). Regardless of the ALT level, all samples with S/COs < or =10 were negative for HCV RNA. Of the samples with S/CO values >10, the optimal cut-off was 40 with sensitivity and specificity for both of 81%. In conclusion, subjects with S/CO values < or =10 (10.7%) were more likely to be cases of past infection or of non-specific reaction. Most (90%, 108/120) of the subjects with S/COs >40 represent current or persistent infection. To predict viremia in subjects with S/COs between 10 and 40, 6.7% of all anti-HCV-positive subjects was invalid by a cross-sectional observation.
  
  
  CONCLUSIONS
  Follow-up or further study is recommended. The third-generation EIA test plays a semiquantitative role for the prediction of viremia in HCV infection.
authors.affiliation: Division of Hepatogastroenterology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, ROC.
authors.forename: Wu-Shiung
authors.initials: WS
authors.lastname: Huang
authors.forename: Sheng-Nan
authors.initials: SN
authors.lastname: Lu
authors.forename: Jing-Houng
authors.initials: JH
authors.lastname: Wang
authors.forename: Chuan-Mo
authors.initials: CM
authors.lastname: Lee
authors.forename: Hung-Da
authors.initials: HD
authors.lastname: Tung
authors.forename: Tsung-Ming
authors.initials: TM
authors.lastname: Chen
authors.forename: Chi-Sin
authors.initials: CS
authors.lastname: ChangChien
mesh_terms: D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000276:immunology / Q000821:virology*; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D007124:Immunoenzyme Techniques; D008111:Liver Function Tests; D008403:Mass Screening; D011237:Predictive Value of Tests; D011379:Prognosis; D012367:RNA, Viral / Q000097:blood; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D015203:Reproducibility of Results; D014766:Viremia / Q000175:diagnosis / Q000276:immunology / Q000821:virology*
chemical_list: D018937:Hepatitis C Antibodies; D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic