title: Two HBV DNA+/HBsAg- blood donors identified by HBV NAT in Shenzhen, China.
abstract: BACKGROUND
  In order to further improve blood safety, mini-pool (MP) nucleic acid testing (NAT) was implemented to screen samples negative for hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (anti-HCV), anti-human immunodeficiency virus (anti-HIV), syphilis (anti-Treponemal antibody) and with normal ALT.
  
  
  METHODS
  From August 2006 to February 2008, 41,301 donations were screened using commercial HIV/HCV RNA and HBV DNA Real-Time PCR NAT assays in pools of 8. Reactive pools were re-tested as individual samples using the appropriate screening test and confirmed using an alternate commercial NAT assay. Donors reactive on both NAT assays were considered 'confirmed' positive for the virus concerned and recalled for additional follow-up testing and counseling.
  
  
  RESULTS
  Of the 41,301 samples screened, no HIV or HCV RNA-positive/seronegative donations were detected but two HBV DNA positive/HBsAg negative blood donors (Donors 1 and 2) were identified. Their respective hepatitis immunological markers were: Donor 1 - anti-HBc positive/anti-HBe positive/HBeAg negative/ALT normal and HBV DNA viral load of 112 IU/ml; Donor 2 - anti-HBc positive/anti-HBe negative/HBeAg negative/ALT normal and HBV DNA viral load 2750 IU/ml.
  
  
  CONCLUSIONS
  MP NAT identified two HBsAg negative donors with presumed occult infection but no HIV or HCV seronegative/NAT positive (yield) donors. The HBV yield rate of 1 in 20,650 (95%CI - 1 in 5663 to 1 in 75,303) is comparatively high, exceeds the predicted rate based on previous modeling for the population and demonstrates the incremental blood safety value of NAT in countries where HBV is highly epidemic. The low viral load of the two yield samples underscores the importance of optimizing the sensitivity of the HBV NAT assay selected for screening.
authors.affiliation: Shenzhen Blood Center, Shenzhen, Guangdong Province, People's Republic of China.
authors.forename: Guifang
authors.initials: G
authors.lastname: Shang
authors.forename: Youqing
authors.initials: Y
authors.lastname: Yan
authors.forename: Baocheng
authors.initials: B
authors.lastname: Yang
authors.forename: Chaopeng
authors.initials: C
authors.lastname: Shao
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Clive R
authors.initials: CR
authors.lastname: Seed
mesh_terms: D000914:Antibodies, Viral / Q000097:blood / Q000235:genetics; D001782:Blood Donors; D001803:Blood Transfusion / Q000592:standards; D002681:China; D004279:DNA, Viral / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D015658:HIV Infections / Q000097:blood; D006509:Hepatitis B / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000302:isolation & purification; D006526:Hepatitis C / Q000097:blood; D006801:Humans; D018579:Patient Selection; D016133:Polymerase Chain Reaction / Q000379:methods; D012367:RNA, Viral / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D012449:Safety; D013587:Syphilis / Q000097:blood
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D012367:RNA, Viral