title: What is the meaning of a nonresolved viral nucleic acid test-reactive minipool?
abstract: BACKGROUND
  This study aimed at analyzing the prevalence of hepatitis B virus (HBV) DNA among hepatitis B surface antigen (HBsAg)-negative donations by cobas TaqScreen MPX test (Roche Molecular Systems) and discussing the meaning of a reactive minipool (MP) that does not resolve to an individual donation (ID)-reactive result.
  
  
  METHODS
  Nucleic acid amplification testing (NAT) was performed in 12 Chinese blood centers on 826,044 serologic negative donations in MPs of six. MP-reactive pools that were resolved to ID-reactive donations were confirmed by Roche TaqMan viral load assays. Antibody to hepatitis B surface antigen and antibody to hepatitis B core antigen (anti-HBc) results were also analyzed. Cycle threshold (Ct) values of reactive MPs were analyzed in relation to the probability of pool resolution.
  
  
  RESULTS
  A total of 1267 of 137,674 pools were reactive, of which 839 donations were reactive by ID-NAT. The MP6 HBV NAT-yield rate lay between 1 in 1600 and 1 in 1000. At MP Ct values equal or below 37, the probability of pool resolution was approximately 80%. The prevalence of anti-HBc in ID-reactive donations was 81%. The proportion of reactive pools that could not be resolved was 36%. The prevalence of anti-HBc in donations implicated in nonresolved MPs was significantly higher than those in nonreactive MPs (48% vs. 37%, p = 0.016).
  
  
  CONCLUSIONS
  The anti-HBc data suggest that approximately 10% of nonresolved MPs contain HBV DNA from a low-viral-load occult carrier. We consider ID-NAT resolution testing in duplicate to minimize HBV transmission risk associated with transfusing nonreactive donations implicated in reactive MPs.
authors.affiliation: National Center for Clinical Laboratories, Beijing Hospital, Beijing, China.
authors.forename: Lunan
authors.initials: L
authors.lastname: Wang
authors.forename: Le
authors.initials: L
authors.lastname: Chang
authors.forename: Yunzheng
authors.initials: Y
authors.lastname: Xie
authors.forename: Chengyin
authors.initials: C
authors.lastname: Huang
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Rong
authors.initials: R
authors.lastname: Qian
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhu
authors.forename: Yaqin
authors.initials: Y
authors.lastname: He
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Hongliang
authors.initials: H
authors.lastname: Huang
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.forename: Kuo
authors.initials: K
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Jiehong
authors.initials: J
authors.lastname: Xie
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.forename: Jinming
authors.initials: J
authors.lastname: Li
mesh_terms: D001782:Blood Donors; D004279:DNA, Viral / Q000097:blood*; D046148:Donor Selection / Q000379:methods*; D005260:Female; D006509:Hepatitis B / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood*; D006515:Hepatitis B virus; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D015995:Prevalence; D019562:Viral Load / Q000379:methods
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies