title: Hepatitis B virus DNA-positive, hepatitis B surface antigen-negative blood donations intercepted by anti-hepatitis B core antigen testing: the Canadian Blood Services experience.
abstract: BACKGROUND
  The benefit of introducing anti-hepatitis B core antigen (HBc) screening for intercepting potentially infectious donations missed by hepatitis B surface antigen (HBsAg) screening in Canada was studied.
  
  
  METHODS
  Anti-HBc testing of all donations was implemented in April 2005, along with antibody to hepatitis B surface antigen (anti-HBs) and hepatitis B virus (HBV) DNA supplemental testing of anti-HBc repeat-reactive, HBsAg-negative donations. The proportion of potentially infectious donations intercepted by anti-HBc over the initial 18 months of testing was calculated based on three assumptions relating infectivity of HBV DNA-positive units to anti-HBs levels. Lookback was conducted for all DNA-positive donations.
  
  
  RESULTS
  Of 493,344 donors, 5,585 (1.13%) were repeat-reactive for the presence of anti-HBc, with 29 (0.52%) being HBV DNA-positive and HBsAg-negative. The proportion of potentially infectious donations intercepted by anti-HBc screening was 1 in 17,800 if all HBV DNA-positive donations were infectious, 1 in 26,900 if infectivity was limited to donations with an anti-HBs level of not more than 100 mIU per mL, and 1 in 69,300 if only donations with undetectable anti-HBs were infectious. For 279 components in the lookback study, no traced recipients were HBsAg-positive and 7 recipients were anti-HBc-reactive in association with 4 donors, 3 of whom had an anti-HBs level of more than 100 mIU per mL and 1 of whom had a level of 61 mIU per mL.
  
  
  CONCLUSIONS
  Implementation of anti-HBc screening reduced the risk of transfusing potentially infectious units by at least as much as had been expected based on the literature. The lookback did not provide proof of transfusion transmission of HBV from HBV DNA-positive, anti-HBc-reactive, HBsAg-negative donors but it did not establish lack of transmission either.
authors: National Epidemiology and Surveillance, Canadian Blood Services, 1800 Alta Vista Drive, Ottawa, Ontario, Canada. sheila.o'brien@bloodservices.ca
authors: Sheila F
authors: SF
authors: O'Brien
authors: Margaret A
authors: MA
authors: Fearon
authors: Qi-Long
authors: QL
authors: Yi
authors: Wenli
authors: W
authors: Fan
authors: Vito
authors: V
authors: Scalia
authors: Irene R
authors: IR
authors: Muntz
authors: Eleftherios C
authors: EC
authors: Vamvakas
mesh_terms: D001782:Blood Donors / Q000706:statistics & numerical data*; D001803:Blood Transfusion / Q000592:standards*; D002170:Canada; D003140:Communicable Disease Control; D004279:DNA, Viral / Q000097:blood*; D006509:Hepatitis B / Q000097:blood / Q000517:prevention & control / Q000635:transmission; D006512:Hepatitis B Core Antigens / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000302:isolation & purification*; D006801:Humans; D012984:Software
chemical_list: D004279:DNA, Viral; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens