What can be revealed by extending the sensitivity of HBsAg detection to below the present limit?
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.
Togashi
Hitoshi
H
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
Hashimoto
Chika
C
Yokozawa
Junji
J
Suzuki
Akihiko
A
Sugahara
Kazuhiko
K
Saito
Takafumi
T
Yamaguchi
Ichiro
I
Badawi
Hala
H
Kainuma
Norikazu
N
Aoyama
Masaaki
M
Ohya
Hiroaki
H
Akatsuka
Takao
T
Tanaka
Yasuhito
Y
Mizokami
Masashi
M
Kawata
Sumio
S
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
D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens