title: Systematic review of the accuracy of antibody tests used to screen asymptomatic adults for hepatitis C infection.
abstract: BACKGROUND
  Several expert groups, including the United States Preventive Services Task Force and the Canadian Task Force on Preventive Health Care, have recently examined or are currently examining whether primary care physicians should screen asymptomatic adults for hepatitis C virus (HCV) infection. To inform decision-making on HCV screening, we performed a systematic review of the accuracy of antibody tests compared with other immunoassays and RNA detection for screening asymptomatic adults for HCV infection in Canada.
  
  
  METHODS
  MEDLINE and Embase databases were searched from 1990 to 2016; resulting citations were uploaded into DistillerSR and independently screened by 2 reviewers. Original research studies, systematic reviews and meta-analyses were eligible for inclusion. At least 80% of the study population had to be asymptomatic, nonpregnant, treatment-naïve adults with unknown liver enzyme values and unknown HCV status. Risk of bias was assessed with the use of the Quality Assessment of Diagnostic Accuracy Studies version 2 (QUADAS-2) tool; the quality of the body of evidence was assessed by means of GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology.
  
  
  RESULTS
  Of 1537 articles identified, 81 underwent full-text review, and 9 studies met the inclusion criteria. Compared with RNA detection, the sensitivity of the third-generation enzyme-linked immunosorbent assay was variable (61.0%-81.8%), and its specificity was high (97.5%-99.7%). As expected, there were more false-positive results when comparing antibody tests to RNA detection than to other immunoassays. Our GRADE assessment suggested that there was a high concern for risk of bias, particularly verification bias, and substantial inconsistency between studies in terms of their design.
  
  
  CONCLUSIONS
  More research is needed to better characterize the accuracy of antibody tests used to screen for HCV infection in the general population. Jurisdictions that recently adopted birth cohort screening for HCV infection are encouraged to evaluate and report on the accuracy of HCV screening tests and screening benefits and harms.PROSPERO registration:no. CRD42016039710.
authors.affiliation: Dalla Lana School of Public Health (Cadieux, Campbell), University of Toronto, Toronto, Ont.; Department of Epidemiology, Biostatistics and Occupational Health (Dendukuri), McGill University, Montréal, Que.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Cadieux
authors.affiliation: Dalla Lana School of Public Health (Cadieux, Campbell), University of Toronto, Toronto, Ont.; Department of Epidemiology, Biostatistics and Occupational Health (Dendukuri), McGill University, Montréal, Que.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Campbell
authors.affiliation: Dalla Lana School of Public Health (Cadieux, Campbell), University of Toronto, Toronto, Ont.; Department of Epidemiology, Biostatistics and Occupational Health (Dendukuri), McGill University, Montréal, Que.
authors.forename: Nandini
authors.initials: N
authors.lastname: Dendukuri