The rate of HBsAg carriers among blood donors at at Thua Thien Hue province during 5 years (1997 - 2001) is relative high, with 13.57% on average. At the same time, the incidence of HCV infection is lower than other areas (with mean 0.64%). The rate of HBsAg carrier is higher in rural than in Hue city (14.72% vs. 12.27%). The young adults in precincts have higher HBsAg incidence than in other groups.
Blood Donors ; Hepatitis B Surface Antigens ; Hepatitis C Antibodies

<b>OBJECTIVEb>Establish a confirmatory test based on ELISA, and use to verify the authenticity of HBsAg weak positive samples, pick and get rid of the false result, and avoid the mistake diagnosis.

<b>METHODb>The particles (reagent A) coated by streptavidin and biotinylated HBsAb (reagent B) were mixed in different proportions, then neutralized with serum whose the COI of HBsAg > 20 by ELISA in order to identify the activity of HBsAb in confirmatory reagent. 30 pieces of HBsAg weak positive serum neutralized with the confirmatory reagent, the serum were considered to be positive if rate of decline of HBsAg COI > 50%. The results were compared to Roche confirmatory Kit.

<b>RESULTb>Confirmatory reagent was able to neutralized with HBsAg. 24 of 30 pieces of HBsAg weak positive samples were judged to be positive, while 6 poeces were negative. The ELISA comfirm method is fully consistent with Roche confirmatory Kit.

<b>CONCLUSIONb>The ELISA confirmatory test for suspicious HBsAg positive samples is a simple, accurate and low cost initial validation method, After further clinical trials, should be widely applied.

Enzyme-Linked Immunosorbent Assay ; methods ; Hepatitis B ; blood ; diagnosis ; Hepatitis B Antibodies ; blood ; Hepatitis B Surface Antigens ; blood ; Humans

<b>OBJECTIVEb>Establish a kind of confirmation method based on ELISA, and use to verify authenticity of HBsAb + in HBsAg + HBsAb + serum, pick and get rid of the false masculine gender the result, and avoid the mistake diagnosis.

<b>METHODb>Collect 60 pieces of serum whose thick degree of HBsAg at 1000 COI above tested by ECLIA as confirm serum, mixed the confirm serum of different dilution with HBsAb positive serum to screen and verify best thick degree of HBsAg. Collected 40 pieces of HBsAg + HBsAb + serum, ELISA tested the descend rate of HBsAb COI after neutralized with confirm serum in order to confirm authenticity of HBsAb + in pieces of HBsAg + HBsAb + serum.

<b>RESULTb>When thick degree of HBsAg is 2000 COI, the performance of neutralization to HBsAb is best. The ELISA confirmatory test is fully consistent with the ECLIA method with true positive of 37 pieces of HBsAg + HBsAb + serum while false-positive of 3 pieces of serum.

<b>CONCLUSIONb>The ELISA confirm method is a simple, accurate and low cost initial validation method.

Enzyme-Linked Immunosorbent Assay ; methods ; Hepatitis B Antibodies ; blood ; Hepatitis B Surface Antigens ; blood ; immunology ; Humans

Alanine Transaminase ; blood ; DNA, Viral ; blood ; Hepatitis B Antibodies ; blood ; Hepatitis B Core Antigens ; blood ; Hepatitis B Surface Antigens ; blood ; Hepatitis B e Antigens ; blood ; Hepatitis B virus ; genetics ; immunology ; Hepatitis B, Chronic ; virology ; Humans

<b>OBJECTIVEb>To investigate the properties of HBsAb in occult hepatitis B virus infection and its affinity to different serotypes of hepatitis B virus surface antigen (HBsAg).

<b>METHODSb>Long-term follow-up was conducted in 2 HBsAb positive patients with occult hepatitis B virus infection. HBsAg was detected using multiple diagnostic kits and the HBsAb subtype was determined by performing neutralization experiments with different serotypes of HBsAg. The viral S gene was PCR-amplified and mutation analysis was conducted. Plasmids expressing HBsAgs were constructed by inserting these PCR products into an eukaryotic expression vector and were then transfected into HepG2 cells. The cell culture supernatant and cellular extracts were detected for HBsAg respectively. Neutralization experiments were carried out in the cell culture supernatant from HBsAg plasmids transfected HepG2 cells and serum samples from these patients and others who had been confirmed to be positive for HBsAb.

<b>RESULTSb>Multiple tests using various diagnostic kits showed that the 2 patients were negative for HBsAg and the three different serotypes of HBsAg (adr, adw, ay) could neutralize 82.1%-100% of HBsAb existed in the 2 patients. Sequence analysis of S gene cloned from these patients revealed that the homology to reference strain were 95.13%-97.79% and 92.04%-95.58% respectively at the nucleotide and amino acid levels. Quantitation of HBsAg showed that the expression levels of HBsAg from the two patients were 41.1% and 22.6% respectively of that of control HBsAg in cell culture supernatant and 48.1% and 59.3% respectively in cellular extract, and the supernatant/cell lysate ratios were 0.85 and 0.38 respectively. In neutralization experiments, HBsAg could be totally absorbed by control serum, whereas could only be partially neutralized by HBsAbs from the two patients (F = 353.6 and 645.2, P is less than 0.01).

<b>CONCLUSIONb>Both the antigenicity and the ability of HBsAg secreted outside of the cells are decreased in these HBsAb-positive patients with occult HBV infection. The HBsAbs are mainly specific for common epitopes among different serotypes of HBsAg and are probably different as compared with those produced by vaccine inoculation.

Adult ; Hepatitis B ; blood ; virology ; Hepatitis B Antibodies ; blood ; Hepatitis B Surface Antigens ; blood ; Hepatitis B virus ; Humans ; Male ; Middle Aged ; Serologic Tests

<b>OBJECTIVEb>Through detecting the standard preparation with series of concentration to indirectly calculate the anti-HBs concentration of the serum samples, a suitable anti-HBs quantitative method for our laboratory was found after comparing the two kinds of methods.

<b>METHODSb>Detecting the anti-HBs standard preparation with series of concentration by RIA method, standard curvilinear equations were obtained by the means of fitting the detected result and the corresponding concentration by log-log model and exponential curve model respectively. Then the fitting efficiency of two curves was compared. By calculating the concentrations of the reference using two standard curvilinear equations, we can compare the accuracy of two quantitative methods.

<b>RESULTb>The error mean square of the exponential curve model is low as 1.2971 and the determinate coefficient is close to 1 with the value of 0.9904. The average concentrations (n=6) of the detected reference calculated by two curvilinear equation with the actual concentration of 30.0 mIU/mL are (32.28 +/- 1.06) and (31.91 +/- 1.06) mIU/ mL respectively. The concentration calculated by exponential curve model is only 6.37% higher than the actual concentration.

<b>CONCLUSIONb>Fitting by exponential curve model is more practical to estimate the actual concentration of the serum samples those will be detected. It can be used as an optimal quantitative method to detect anti-HBs concentration.

Hepatitis B ; blood ; immunology ; virology ; Hepatitis B Antibodies ; blood ; immunology ; Hepatitis B Surface Antigens ; blood ; immunology ; Hepatitis B virus ; immunology ; isolation & purification ; Humans ; Male ; Radioimmunoassay ; methods

<b>OBJECTIVEb>To better understand the proportions of reported hepatitis B cases in pilot surveillance cites through investigation and laboratory testing.

<b>METHODSb>To confirm the reported cases of hepatitis B by collecting blood specimen and laboratory testing on HBsAg, IgM of Anti-HBc, Anti-HAV in 18 pilot surveillance counties.

<b>RESULTSb>Among 2858 cases of hepatitis B reported in 2006, 23.97% of them were reported as suspected acute cases, 14.87% as acute cases, 20.33% as suspected chronic cases, 34.67% as chronic cases, 4.09% as cirrhosis and 2.06% as HCC. Among 1681 reported hepatitis B cases confirmed by laboratory testing, results showed that 24.16% of them were diagnosed as acute hepatitis B, but only 15.37% were confirmed as acute hepatitis B. Although the proportion confirmed as hepatitis B kept consistent as before, misclassification was found.

<b>CONCLUSIONb>In current surveillance system, reported hepatitis B cases were mainly chronic, only up to one third belonged to acute hepatitis B. The reported incidence of hepatitis B did not reflect the real incidence due to misclassification. To better define the burden on hepatitis B disease, it was necessary and urgent to revise the diagnostic criteria and to conduct surveillance on hepatitis B, under separate reporting categories which including acute and chronic cases of the disease.

China ; epidemiology ; Hepatitis B ; diagnosis ; epidemiology ; Hepatitis B Antibodies ; blood ; Humans ; Incidence ; Pilot Projects ; Population Surveillance

Hepatitis B ; prevention & control ; Hepatitis B Antibodies ; blood ; Hepatitis B Vaccines ; immunology ; Humans ; Immune Tolerance ; Risk Factors ; Vaccination

Occult HBV infection is characterized by the absence of serum HBsAg with persistence of low level of intrahepatic HBV DNA. Several suggested mechanisms for the origin of occult HBV infection include strong suppression of viral replication and gene expression, mutation in the regulatory regions of HBV genome, formation of immunoglobulin-bound HBsAg, viral interference, and blockage of HBsAg secretion from infected hepatocytes. Standardized assays are not yet available, and sensitive HBV DNA amplification assay is necessary for the diagnosis of cryptic infection. Detection rate of HBV DNA is highest in IgG anti-HBc positive population. However, neither anti-HBc nor anti-HBs can be detected in a significant proportion of infected persons. Occult HBV infection occurs in a number of clinical settings and is highly prevalent in HCV-infected patients as well as in patients with cryptogenic chronic liver disease including hepatocellular carcinoma.
DNA, Viral/analysis ; Hepatitis B/*diagnosis/*epidemiology/metabolism ; Hepatitis B Antibodies/blood ; Hepatitis B Core Antigens/immunology ; Hepatitis B Surface Antigens/blood ; Humans

Hepatitis B ; immunology ; virology ; Hepatitis B Antibodies ; blood ; Hepatitis B e Antigens ; blood ; Hepatitis B virus ; immunology ; physiology ; Humans ; Immunologic Tests ; methods ; Virus Replication