title: Indeterminate RIBA results were associated with the absence of hepatitis C virus RNA (HCV-RNA) in blood donors.
abstract: BACKGROUND
  Hepatitis C virus (HCV) infection is diagnosed by the presence of antibodies and is supplemented by confirmatory testing methods, such as recombinant immunoblot assay (RIBA) and HCV-RNA detection. This study aimed to evaluate the efficacy of RIBA testing to diagnose HCV infection in blood donors positive for anti-HCV antibodies.
  
  
  METHODS
  A total of 102 subjects positive for anti-HCV determined by enzyme-linked immunosorbent assay (ELISA) at the Hematology and Hemotherapy Foundation of Bahia (HEMOBA) were later assessed with new samples using the Abbott Architect anti-HCV test (Abbott Diagnostics, Wiesbaden, Germany), the RIBA III test (Chiron RIBA HCV 3.0 SIA, Chiron Corp., Emeryville, CA, USA), the polymerase chain reaction (PCR; COBAS® AMPLICOR HCV Roche Diagnostics Corp., Indianapolis, IN, USA) and line probe assay (LiPA - Siemens, Tarrytown, NY, USA) genotyping for HCV diagnosis.
  
  
  RESULTS
  Of these new samples, 38.2% (39/102) were positive, 57.8% (59/102) were negative and 3.9% (4/102) were indeterminate for anti-HCV; HCV-RNA was detected in 22.5% (23/102) of the samples. RIBA results were positive in 58.1% (25/43), negative in 9.3% (4/43) and indeterminate in 32.6% (14/43) of the samples. The prevailing genotypes were 1 (78.3%, 18/23), 3 (17.4%, 4/23) and 2 (4.3%, 1/23). All 14 samples with indeterminate RIBA results had undetectable viral loads (detection limit ≤50 IU/mL). Of these samples, 71.4% (10/14) were reevaluated six months later. Eighty percent (8/10) of these samples remained indeterminate by RIBA, and 20% (2/10) were negative.
  
  
  CONCLUSIONS
  In this study, individuals with indeterminate RIBA results had no detectable HCV-RNA.
authors.affiliation: Laboratório Central de Saúde Pública do Estado da Bahia, Secretaria da Saúde, SalvadorBA, Laboratório Central de Saúde Pública do Estado da Bahia, Secretaria da Saúde, Salvador, BA.
authors.forename: Felicidade Mota
authors.initials: FM
authors.lastname: Pereira
authors.affiliation: Laboratório Central de Saúde Pública do Estado da Bahia, Secretaria da Saúde, SalvadorBA, Laboratório Central de Saúde Pública do Estado da Bahia, Secretaria da Saúde, Salvador, BA.
authors.forename: Maria Alice Sant'ana
authors.initials: MA
authors.lastname: Zarife
authors.affiliation: Laboratório de Patologia e Biologia Molecular, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, SalvadorBA, Laboratório de Patologia e Biologia Molecular, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, BA.
authors.forename: Eliana Almeida Gomes
authors.initials: EA
authors.lastname: Reis
authors.affiliation: Laboratório de Patologia e Biologia Molecular, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, SalvadorBA, Laboratório de Patologia e Biologia Molecular, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, BA.
authors.forename: Mitermayer
authors.initials: M
authors.lastname: G Reis
mesh_terms: D000328:Adult; D001782:Blood Donors; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000235:genetics* / Q000276:immunology; D006526:Hepatitis C / Q000175:diagnosis*; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D015151:Immunoblotting; D008297:Male; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000097:blood*; D011994:Recombinant Proteins; D019562:Viral Load
chemical_list: D018937:Hepatitis C Antibodies; D012367:RNA, Viral; D011994:Recombinant Proteins