title: Hepatitis B virus nucleic acid amplification testing of Australian blood donors highlights the complexity of confirming occult hepatitis B virus infection.
abstract: BACKGROUND
  We present an analysis of the first 2 years of hepatitis B virus (HBV) nucleic acid testing (NAT) of the Australian donor population.
  
  
  METHODS
  Between July 5, 2010, and July 4, 2012, all blood donations were screened for HBV DNA and hepatitis B surface antigen (HBsAg). Donors who tested HBsAg negative but HBV NAT positive were assessed as occult hepatitis B infections (OBI) if reactive for antibodies to HBV core antigen (anti-HBc). Donors who were anti-HBc reactive but with nonrepeatable or nondiscriminated NAT results were assessed as HBV inconclusive pending follow-up testing.
  
  
  RESULTS
  During the study period a total of 2,673,521 donations were screened for HBV. Forty-two chronic OBI infections (5.55/100,000 donors) were identified compared to eight acute serologic window period infections (1.06/100,000 donors). Of the 42 OBI cases, 23 (54.8%) were detected the first time they were screened for HBV DNA while 19 (45.2%) gave one or more HBV NAT-nonreactive results before detection. Of 68 donors initially assessed as HBV inconclusive and available for follow-up, 10 later confirmed as OBI cases while 51 were NAT nonreactive but remained anti-HBc reactive and OBI could not be excluded.
  
  
  CONCLUSIONS
  This study demonstrated a substantially higher prevalence of OBI compared to acute serologic window period HBV infections in Australian blood donors. Follow-up testing of OBI cases indicates that HBV DNA is often only intermittently detectable in OBI, highlighting the importance of including anti-HBc to optimize the HBV testing algorithm.
authors.affiliation: Australian Red Cross Blood Service, Melbourne, Australia.
authors.forename: Philip
authors.initials: P
authors.lastname: Kiely
authors.forename: Angelo R
authors.initials: AR
authors.lastname: Margaritis
authors.forename: Clive R
authors.initials: CR
authors.lastname: Seed
authors.forename: Hung
authors.initials: H
authors.lastname: Yang
mesh_terms: D000328:Adult; D000465:Algorithms; D058070:Asymptomatic Diseases; D001315:Australia / Q000453:epidemiology; D004279:DNA, Viral / Q000097:blood*; D046148:Donor Selection; D006509:Hepatitis B / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D006510:Hepatitis B Antibodies / Q000097:blood*; D006512:Hepatitis B Core Antigens / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000235:genetics / Q000302:isolation & purification*; D019694:Hepatitis B, Chronic / Q000097:blood / Q000175:diagnosis; D006801:Humans; D021141:Nucleic Acid Amplification Techniques; D015995:Prevalence; D012306:Risk; D013997:Time Factors; D019562:Viral Load; D014766:Viremia / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens