Frequency of hepatitis B antigen in blood donors

Routine testing of all blood donations for hepatitis B antigen by counter-immunoelectrophoresis was started in April 1971. The frequency of HBAg carriers among apparently healthy volunteer blood donors in the Toronto Centre of the Canadian Red Cross Blood Transfusion Service was 15 in 10,000 with a male:female ratio of 6:1. Excluding penitentiary inmates, the highest incidence was among young, male, non-Anglo-Saxon city dwellers.A system of notification of HBAg-positive donors was developed, through which a carrier is referred to a special clinic for clinical and pathological evaluation.A survey of hospital patients indicated an incidence of HB antigen 3.5 times that of our healthy donor population. A comparison of the number of post-transfusion hepatitis cases occurring before and after the commencement of routine testing for HBAg showed a marked reduction in reported cases in 1971.     

Comparative infectious serology testing of pre- and post-mortem blood samples from cornea donors

Defined serological blood tests of deceased cornea donors are required to minimize the risk of viral infections of a transplant recipient as much as possible. Haemolysis, autolysis and bacterial contamination, may produce significant changes of post-mortem blood samples, which may lead to false serological test results. Pre- and post-mortem findings from the same cornea donors of the University Tissue Bank of the Charité in the years 2004-2009 (n?=?487) were retrospectively analyzed and compared. The test results from pre-mortem blood samples were defined as the reference for the post-mortem blood test. Of 487 cornea donors, there were a total of 21 cases (4.3?%) with discrepancies between serological test results from pre- and post-mortem blood samples. Of these, 7 values referred to the HBsAg-testing, 3 to the anti-HBs-, 1 to the anti-HBcIgG?+?IgM-, 1 to the anti-HCV-, 4 to the anti-HIV 1/2- and 5 to the TPLA-findings. False negative results within post-mortem serology occurred in 4 of 487 cases (0.8?%). False positive results within the post-mortem blood samples occurred at a much more frequent rate, with 17 of 487 cases (3.5?%). Discrepancies between serological pre- and post-mortem blood tests occur mainly due to the use of non-validated test systems. Therefore, it seems reasonable to test pre- and post-mortem blood samples serologically, whenever possible, at the same time, regardless of the sample age. Positive results, regardless of the sample type, should always be retested with validated confirmation tests (e.g. NAT), in order to differentiate between false and true positive results.     

Detection of hepatitis B virus in bone allografts from donors with occult hepatitis B infection

The implementation of nucleic acid testing in donor screening has improved the safety of tissue allografts. Although infectious disease transmission can be considered a rare event, the detection of occult hepatitis B infection remains challenging. The studies concerning this risk are mainly based on testing blood specimens. This work shows the correlation between results of samples obtained from donor blood and the corresponding tissue washing solution. Hepatitis B virus deoxyribonucleic acid was detected both in bone allografts from donors with serological profiles associated to active hepatitis B infection and occult hepatitis B infection. These results suggest that hepatitis B virus seems to concentrate in bone marrow even when a low viral load is present in peripheral blood. Even detection at molecular level is not enough to avoid the risk of hepatitis B virus transmission and a multiparametrical evaluation is required in tissue donor screening. The role of clinicians in recognition and reporting of allograft-associated infections is a major concern for the acquisition of experience to be applied in risk control of disease transmission.     

Prevalence of hepatitis B viral markers in Vietnamese blood donors

Serum samples were assayed using radioimmunoassay in 573 Vietnamese blood donors living in Hano? (North Viet Nam). 66 (11.5%) subjects were HBsAg-positive. Of these 66 HBsAg carriers, 17 (25,8%) were positive for hepatitis B e antigen (HBeAg) and 43 (65.1%) for antibody to HBeAg (anti-HBe). 22 (3.8%) subjects were positive for antibody to hepatitis B core antigen (anti-HBc) alone. 402 (70.2%) subjects were positive for antibody to HBsAg (anti-HBs). This anti-HBs percentage increased with age. Only 83 (14.5%) subjects were negative for all hepatitis B viral (HBV) markers. This no HBV markers percentage decreased with age. The chi 2 test showed a non significant difference for frequencies of HBsAg, anti-HBc alone, anti-HBs but a significant one for frequencies of no HBV markers in men and women.     

Chaos reigns at medical schools over hepatitis B testing

Health Canada guidelines require that all physicians be immunized against hepatitis B--a policy that the CMA opposes. Where does that leave medical students?     

Screening of Danish blood donors for hepatitis B surface antigen using a third generation technique.

The profit to be gained by testing Danish blood donors for hepatitis B surface antigen (HBsAg) with a third generation technique instead of the currently used immunoelectrophoresis was investigated by additional screening of 48 750 blood units by radioimmunoassay three weeks after donation. Twenty nine units were positive for HBsAg on radioimmunoassay (0.059%). Only six of these were found by immunoelectrophoresis (0.012%). Most of the 23 donors positive on radioimmunoassay and negative on immunoelectrophoresis were healthy carriers of HBsAg (20) or had asymptomatic chronic liver disease (two). One donor had acute hepatitis B. Fifteen of the 23 blood units were transfused. The 15 recipients were monitored biochemically and serologically for up to nine months. One recipient developed fulminant hepatitis B, three developed acute hepatitis B, and one became a healthy carrier of HBsAg. All these patients had received blood from healthy carriers of HBsAg. Two recipients were immunised against HBsAg, and in one patient no seroconversion was observed. The remaining recipients died soon after transfusion or were protected by antibodies to HBsAg that had been present before the transfusion. Testing of Danish blood donors using a third generation technique identified a substantial number of donors positive for HBsAg overlooked by immunoelectrophoresis. Most of these donors were healthy carriers of HBsAg. Blood taken from such carriers is highly infectious when transfused, probably because of the large amount of material transmitted.     

Hepatitis B virus DNA and e antigen in serum from blood donors in the United Kingdom positive for hepatitis B surface antigen.

Serum samples from 214 blood donors in the United Kingdom who were carriers of hepatitis B surface antigen (HBsAg) were examined for hepatitis B virus deoxyribonucleic acid (DNA) by DNA:DNA hybridisation and for hepatitis B e antigen (HBeAg) and its antibody. One fifth of the donors carried infectious virus in their circulation. The presence of hepatitis B virus DNA correlated well with that of HBeAg, although hepatitis B virus DNA was found in five serum samples that were negative for HBeAg. It is concluded that analysis of serum samples for hepatitis B virus DNA by hybridisation should be the method of choice for determining whether carriers of HBsAg are infectious.     

Hepatitis B antigen: distribution of ad and ay subtypes in blood donors and hepatitis patients

Hepatitis B antigen (HBAg) from blood donors and patients with hepatitis was tested for ad and ay subspecificity by immunodiffusion in agarose. A total of 59 sera from blood donors and 81 sera from hepatitis patients were subtyped.Subtyping of HBAg from blood donors showed ad and ay subspecificity in 64.4 and 35.6% of cases respectively. Patients'' sera on the other hand showed HBAg with ad and ay subspecificity in 6 and 94% of cases respectively. Therefore, ad subtype was more frequently associated with blood donors whereas ay subtype was predominant among hepatitis patients. The relationship between clinical findings and HBAg subtype is also discussed.     

Feasibility of routine testing for hepatitis B surface antigen in hospital employees and restriction of carriers.

In 1972-73, 48 hospital staff members were tested selectively for hepatitis B surface antigen (HBsAg); 4 (8.3%) were found to be HBsAg-positive. In 1974-75, 1415 staff members were tested routinely before employment and at periodic health examination; 25 (1.8%) were found to be HBsAg-positive. Of the HBsAg-positive staff members 55.2% were Asians, this proportion being significantly (P less than 0.05) greater than that of any other ethnic group, and 31.0% were southern Europeans. Nurses and laboratory technologists were the largest professional groups among the HBsAg-positive staff, each accounting for 20.7%. Our results indicate that it is impractical to carry out routine testing of hospital staff for HBsAg. Selective testing and restriction from work in their units is proposed for staff of the renal and peritoneal dialysis units, the emergency department and the intravenous team and dietary staff who handle food directly.     

New strategies for blood donor screening for hepatitis B virus: nucleic acid testing versus immunoassay methods

Serologic testing for hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBV core antigen (anti-HBc) has historically been the foundation of blood screening, while HBV nucleic acid testing (NAT) was recently developed to detect HBsAg-negative, anti-HBc-negative blood units donated during early acute infection. Comparison data on seroconversion panels using HBsAg assays of varying sensitivities and pooled- or single-sample NAT, along with viral load estimates corresponding to HBsAg assay detection limits, have provided information on the theoretical benefits of NAT relative to HBsAg. Model-derived estimates have generally been predictive of the yields of DNA-positive, HBsAg-negative window period blood units detected in a number of studies from Europe, Japan, and the US. Studies indicate that the added benefit of pooled-sample NAT is relatively small in areas of low endemicity, with greater yields in areas highly endemic for HBV. Single-sample NAT would offer more significant early window period closure and could prevent a moderate number of residual HBV transmissions not detected by HBsAg assays; however, no fully automated single-sample HBV NAT systems are currently available.Even single-sample HBV NAT may not substitute for anti-HBc screening, as indicated by studies of donors with isolated anti-HBc who have extremely low DNA levels undetectable by standard single-sample NAT and who have been associated with transfusion-transmitted HBV. Moreover, HBsAg testing may still be needed even in the setting of combined anti-HBc and NAT screening. HBsAg-positive units from donors in the chronic stage of infection may contain very low or intermittently detectable DNA levels that single-sample NAT would miss. Although such donors are usually anti-HBc reactive and would be interdicted by anti-HBc screening, some lack anti-HBc. Extensive parallel testing will be needed to determine whether single-sample NAT in combination with anti-HBc might be sufficient to detect all the infectious donors currently interdicted by HBsAg testing. In countries that do not screen for anti-HBc, HBsAg testing would be the only means of detecting donations from chronically infected individuals with low/intermittently detectable DNA, since even single-donor NAT would not identify these potentially infectious blood units. In the future, the current fully automated HBsAg assays may incorporate significant sensitivity improvements, and automated single-sample HBV NAT may become a reality. Each country will need to develop its blood screening strategy based on HBV endemicity, yields of infectious units detected by different serologic/NAT screening methods, and cost effectiveness of test methods in ensuring blood safety.     

Prevalence of antibodies to hepatitis B core antigen in blood donors in the middle West region of Brazil

The prevalence of antibodies to hepatitis B core antigen in 552 prime blood donors was of 9.4%. The majority (71.2%) has antibodies to hepatitis B surface antigen. The hepatitis B surface antigen was present in 0.7%, all of them antibodies to hepatitis B core antigen positive.     

Multiplication of hepatitis B virus in fulminant hepatitis B.

The presence in serum of hepatitis B e antigen (HBeAg) and hepatitis B virus DNA, which are each regarded as reflecting multiplication of hepatitis B virus, were looked for one to five days after the onset of hepatic encephalopathy in 64 patients with fulminant hepatitis B. HBeAg and hepatitis B virus DNA were found in the serum of only 24 (37%) and six (9%) patients, respectively. Hepatitis B virus DNA was absent from the serum in all 13 patients positive for anti-HBs. These findings indicate that replication of hepatitis B virus stopped after the onset of hepatic encephalopathy in most of the patients and support the view that an enhanced immune response stops the replication. Agents that inhibit viral multiplication would probably not have any effect at this stage of the disease.     

Prevalence of hepatitis B virus in chronic hepatitis B patients

The aim of the current study was to detect HBV by Real time - PCR in chronic hepatitis B patients. Fifty-eight sera of chronic hepatitis B patients were subjected during the period March 2009 to April 2010 in Ilam cities in West of Iran. Sera assayed by real-time PCR and ELISA methods. Twenty serum samples from healthy volunteers and non-hepatitis B patients and negative for hepatitis B seromarkers served as negative controls for the study. Among fifty-eight sera, ELISA showed fifty-five (94.8%) of the samples were positive for HBsAg and three (5.2%) negative results obtained while real-time PCR specified fifty-eight (100%) positive results in chronic hepatitis B patients. HBsAg status did not necessarily reflect HBV DNA level in the serum, as 5.2% of chronic Hepatitis B patients were positive for HBV DNA but negative for HBsAg. HBV DNA was not found to be positive amongst any of the negative controls. Real time - PCR is a sensitive and reproducible assay for HBV DNA quantization.