title: Discordant hepatitis C serological testing in Australia and the implications for organ transplant programs.
abstract: BACKGROUND
  Discordant and equivocal hepatitis C (HCV) serology testing is problematic for making decisions regarding deceased organ donor (DOD) transplant allocation based on allograft infection status.
  
  
  OBJECTIVE
  This study aimed to analyse the prevalence and follow-up testing of discordant HCV tested patients from an Australian population at increased risk of HCV infection, with prevalence modelling for the Australian DOD population.
  
  
  METHODS
  De-identified patient discordant HCV serology results (primary chemiluminescent microparticle immunoassay and secondary Bio-Rad MonoLisa HCV Ag/Ab Ultra assay) were retrospectively identified in a general referral laboratory between May 2008 and August 2011. Prior and follow-up serology testing was reviewed. Discordant result prevalencewas calculated using Bayes' theorem for the DOD population using Australian DOD rates and HCV seroprevalence.
  
  
  RESULTS
  The tested population had a 6.6% HCV seroprevalence. The rate of discordant serotesting was 0.54%, with no cases identified as having definite HCV infection at follow-up. Two patients had evidence of definite HCV seropositivity before the index discordant test. Modelling for the Australian DOD population of 337 per year estimated a discordant test prevalence of 1.8 per year.
  
  
  CONCLUSIONS
  Discordant HCV serotesting may occur for 1 of 185 patients tested in higher risk populations. The majority of such tests represent falsely reactive tests although a small number may reflect partial seroreversion. Amongst Australian DOD, this represents 1 or 2 discordant cases per year. It is likely that if this discordant sample were from a donor with no blood borne virus risk factors, and was concurrently RNA negative, that HCV infectious risk would be extremely low.
authors: School of Medical Sciences, Faculty of Medicine, University of New South Wales, Kensington, NSW 2052, Australia.
authors: A K
authors: AK
authors: Le Page
authors: P
authors: P
authors: Robertson
authors: W D
authors: WD
authors: Rawlinson
mesh_terms: D000328:Adult; D001315:Australia / Q000453:epidemiology; D005260:Female; D016174:Hepacivirus / Q000276:immunology; D006526:Hepatitis C / Q000453:epidemiology* / Q000276:immunology; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D014019:Tissue Donors / Q000706:statistics & numerical data*
chemical_list: D018937:Hepatitis C Antibodies