title: What can be revealed by extending the sensitivity of HBsAg detection to below the present limit?
abstract: OBJECTIVE
  We investigated what can be revealed by extending the sensitivity of HBsAg detection to below the present limit.
  
  
  METHODS
  We examined the sensitivity of this immunoassay in comparison with real-time PCR detection of HBV DNA using serially diluted sera from HBV carriers. Low HBsAg was measured in 210 healthy volunteers and 368 patients with non-B chronic liver diseases who were negative for HBsAg by a standard EIA method.
  
  
  RESULTS
  The radical immunoassay was able to detect HBsAg at a concentration of 0.025 ng/ml. Low HBsAg was positive in 6 of 210 normal volunteers (2.86%), 5 of 65 non-B, non-C cirrhosis patients (7.69%), 6 of 62 non-B, non-C hepatocellular carcinoma patients (9.68%: p=0.04 vs. volunteers), 12 of 134 chronic hepatitis C patients (8.96%: p<0.02 vs. volunteers), and 11 of 107 hepatocellular carcinoma patients complicated by chronic hepatitis C (10.28%: p<0.008 vs. volunteers). Although no HBV DNA was positive in healthy volunteers, 9 patients with non-B chronic liver diseases were positive for HBV DNA by real-time PCR analysis.
  
  
  CONCLUSIONS
  Increasing the sensitivity of HBsAg detection to below the present limit has revealed that infection with HBV, including occult HBV, is far more endemic than suspected previously.
authors.affiliation: Department of Gastroenterology, Course of Internal Medicine and Therapeutics, Yamagata University Faculty of Medicine, Yamagata University Health Administration Center, 1-4-12 Kojirakawa-machi, Yamagata 990-8560, Japan. htogashi@med.id.yamagata-u.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Togashi
authors.forename: Chika
authors.initials: C
authors.lastname: Hashimoto
authors.forename: Junji
authors.initials: J
authors.lastname: Yokozawa
authors.forename: Akihiko
authors.initials: A
authors.lastname: Suzuki
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Sugahara
authors.forename: Takafumi
authors.initials: T
authors.lastname: Saito
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamaguchi
authors.forename: Hala
authors.initials: H
authors.lastname: Badawi
authors.forename: Norikazu
authors.initials: N
authors.lastname: Kainuma
authors.forename: Masaaki
authors.initials: M
authors.lastname: Aoyama
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ohya
authors.forename: Takao
authors.initials: T
authors.lastname: Akatsuka
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizokami
authors.forename: Sumio
authors.initials: S
authors.lastname: Kawata
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000097:blood; D004279:DNA, Viral / Q000097:blood; D019353:Endemic Diseases; D005260:Female; D006509:Hepatitis B / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D006514:Hepatitis B Surface Antigens / Q000032:analysis / Q000097:blood*; D006515:Hepatitis B virus / Q000235:genetics*; D019698:Hepatitis C, Chronic / Q000097:blood; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008113:Liver Neoplasms / Q000097:blood; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens