Evaluation of a confidential method of excluding blood donors exposed to human immunodeficiency virus

A confidential self-administered questionnaire was given to all donors prior to blood donation (n = 95,917). The questionnaire describes acquired immunodeficiency syndrome (AIDS) high-risk groups and requires the donor to designate his blood for either laboratory purposes or for transfusion. Six-hundred and twenty-seven people (0.65%; 78% men) designated their blood for laboratory purposes. In addition to routine enzyme-linked immunoassay (EIA) screening for human immunodeficiency virus (HIV) antibody, all units from the latter group of donors were tested by Western blot (WB) irrespective of the EIA result. An equal number of donor units was selected from those designating their blood for transfusion (age, sex and clinic matched) and these too were tested by WB irrespective of the EIA result. We found that donors designating their blood for laboratory purposes had a 10 times (vs transfusion-designated controls) to 100 times (vs general donor population) greater exposure to HIV. In the laboratory-designated group, an EIA negative donor was WB positive, yielding an estimated EIA false-negative rate of 16 per million. A confidential questionnaire, as described, is a valuable adjunct in ascertaining high-risk blood donors.     

Prevalence of viral markers among first-time Arab blood donors in Kuwait

BACKGROUND: The aim of this study was to assess the effect of blood donation modes on the prevalence of viral markers among Arab first-time blood donors in Kuwait. STUDY DESIGN AND METHODS: Donor ethnic background was classified as Kuwaiti nationals and non-Kuwaiti Arabs. A total of 26,874 donors were screened in 2002 for the following viral markers: hepatitis C virus antibody (anti-HCV), hepatitis B surface antigen (HBsAg), anti-hepatitis B core antigen (HBc), human immunodeficiency virus-1 and -2 antibody (anti-HIV-1 and -2), HIV p24, and human T lymphotropic virus-I and -II antibody (anti-HTLVI/II). All samples positive for the presence of anti-HBc were tested for anti-HBs. Among these donors, 12,798 were first-time donors of which 74 percent were replacement and 26 percent were volunteers. RESULTS: The prevalence of HCV among replacement donors was significantly higher than the volunteer group. The difference between the two modes of blood donations, however, was not significant for HBsAg. The prevalence of anti-HCV among Kuwaiti national and non-Kuwaiti Arab first-time donors was 0.8 and 5.4 percent, respectively, whereas the prevalence of HBsAg was 1.1 and 3.5 percent, respectively, with the difference being significant at a p level of <0.0001. The difference observed for prevalence of anti-HBc among Kuwaiti national and non-Kuwaiti Arab donors (17 and 33.3%, respectively) was significant (p < 0.0001). Among first-time donors, 13.7 percent were positive for the presence of anti-HBs, indicating that 13.7 percent of the total Arab donor population might have had a previous infection and possible immunity to hepatitis B virus (HBV). CONCLUSION: A high prevalence of HBV and HCV was found among non-Kuwaiti Arab donors. The prevalence of anti-HCV was only significantly higher among replacement versus volunteer first-time donors. Therefore, there is a need to develop a strategic plan that incorporates the diverse background of the blood donors living in Kuwait.     

Relative safety of first‐time volunteer and replacement donors in West Africa

BACKGROUND: A significantly higher level of safety between nonremunerated volunteer and replacement donor blood is assumed. This is supported by global data without stratifying between genuine replacement and paid donors, for first‐time or repeat volunteer, or according to age. STUDY DESIGN AND METHODS: In 2008, first‐time volunteer and replacement donors were identified, and confirmed human immunodeficiency virus antibody (anti‐HIV), hepatitis B surface antigen (HBsAg), and hepatitis C virus antibody (anti‐HCV)‐positive screening results were collated. Data were analyzed according to age and sex between the two types of donors. RESULTS: In 6640 first‐time volunteer and 4360 replacement donors, the prevalence of anti‐HIV and HBsAg (1.03 and 13.8% vs. 1.1 and 14.9%, respectively) was not significantly different. Anti‐HIV prevalence was higher in replacement donors less than age 20 than in first‐time volunteers; the difference was not significant. HBsAg and anti‐HIV confirmed‐positive prevalence was significantly higher in first‐time volunteer donors over age 20. CONCLUSION: In Kumasi, Ghana, viral safety of replacement and first‐time volunteer donors was similar, constituting a single population of donors. Safety increment is provided by repeat donation applicable to either group, through different approaches. A blood unit from replacement donor costs half or less than that from a volunteer donor; similar studies conducted elsewhere in sub‐Saharan Africa may lead to changes in current strategies.     

Hepatitis B e antigen in volunteer and paid blood donors

Sera from 200 volunteer donors and 200 paid blood donors, all positive for hepatitis B surface antigen (HBsAg), were tested for the presence of hepatitis B e antigen (HBeAg).HBeAg was detected in 31 HBsAg- positive paid donors (15%), and in 11 HBsAg-positive volunteer donors (5%) by agar gel diffusion. The presence of HBsAg was associated with higher titers of HBsAg. No significant difference was found in the prevalence of antibody to HBeAg (anti-HBe) in the two donor groups. Rheumatoid factor was not associated with the presence or absence of HBeAg or anti-HBe, indicating that HBeAg is probably not an anti-IgG. These data support the epidemiological evidence that paid blood donors appear to be more likely than volunteer donors to transmit hepatitis B virus infection to recipients of their blood.     

Measures to decrease the risk of acquired immunodeficiency syndrome transmission by blood transfusion. Evidence of volunteer blood donor cooperation

We studied whether volunteers giving blood to the Greater New York Blood Program (GNYBP) cooperated with procedures implementing public health recommendations intended to decrease the risk of acquired immunodeficiency syndrome (AIDS) transmission by blood transfusion. Predonation medical screening was expanded to exclude donors who might be ill with AIDS. To exclude possible asymptomatic carriers of the disease, members of groups at increased risk of AIDS were asked either not to give blood or to give it for laboratory studies. A confidential questionnaire, administered to all donors after medical screening, provided the vehicle for donors to advise the GNYBP whether their donation was for laboratory studies or for patient transfusion. We found that the number of male donors decreased; AIDS-related questions in medical history led to a 2 percent increase in donor rejections; 97 percent of donors said their blood could be used for transfusions; 1.4 percent said their blood could be used for laboratory studies only; and 1.6 percent did not respond. Only units designated for transfusion were released to hospitals. People who indicated that their donation was for laboratory studies had a higher prevalence of markers for hepatitis B virus and of antibodies to cytomegalovirus. White cell counts and helper/suppressor T lymphocyte ratios were not significantly different in the two groups. We conclude that volunteer donors have cooperated with the established procedures. None of the laboratory assays identified blood units donated by individuals who, based on information about AIDS high-risk groups, designated their donation for laboratory studies.     

Infectious disease markers in blood donors in northern Thailand

BACKGROUND: A major epidemic of human immunodeficiency virus type 1 (HIV-1) infections that are primarily due to heterosexual transmission has developed in Thailand since 1988. The epidemic has been most severe in northern Thailand. The blood banks in Chiang Mai began screening donors for HIV-1 antibodies in February 1988 and for p24 antigen in April 1992. STUDY DESIGN AND METHODS: The trends of HIV-1 antibody prevalence were analyzed by type of donor (i.e., paid, replacement, and voluntary) for the period of 1988 through 1993. In addition, the prevalence of HIV-1 p24 antigen and of antibodies to syphilis, hepatitis B surface antigen, and hepatitis C virus was evaluated among blood donors at Chiang Mai University Hospital and the Thai Red Cross blood banks in Chiang Mai. RESULTS: The prevalence of HIV-1 antibodies increased from 0.84 percent in 1988 to 4.04 percent in 1991. Seropositivity was highest in paid professional donors. After discontinuation of the use of paid donors in 1993, HIV-1 antibody prevalence decreased to 3.34 percent. Antibody prevalence in replacement donors increased from 0.56 percent in 1988 to 5.82 percent in 1991. Among 44,446 donors tested, 7 (0.016%) were HIV-1 p24 antigen positive but antibody negative. CONCLUSION: The exclusion of paid donors and the use of p24 antigen testing are justified in northern Thailand. Additional strategies to exclude donors at very high risk and to attract those at low risk for infection should be developed and evaluated to increase blood transfusion safety in this and other, similar populations.     

Infection with hepatitis delta and human immunodeficiency viruses among hemophiliacs in Japan

Two hundred two patients with hemophilia, dependent solely on imported coagulation factor concentrates, were tested for markers of hepatitis B virus infection, antibody to hepatitis delta virus (anti-HD), and antibody to human immunodeficiency virus (anti-HIV). Nine carriers of hepatitis B surface antigen (HBsAg) were identified. Six (66.7%) of them were positive for anti-HD, a prevalence much higher than that in HBsAg carriers without hemophilia in Japan (1/113 or 0.9%, p less than 0.001). Anti-HIV was found in 96 (47.5%), in sharp contrast to the low prevalence (0/1205) in apparently healthy blood donors (p less than 0.001). These results implicated imported plasma products in the transmission of both delta and human immunodeficiency viruses to hemophiliacs. An efficient method for the sterilization of plasma products is warranted to prevent exposure of hemophiliacs to the accompanying pathogenic viruses.     

Viral hepatitis markers in Soviet and American blood donors

A cooperative study was undertaken to compare the frequency of hepatitis viral antigens and antibodies among blood donors in the Soviet Union and the United States. Age- and sex-stratified blood donors were identified and their sera tested for hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to the hepatitis B core antigen (anti-HBc), and antibody to the hepatitis A virus (anti-HAV). A total of 994 Soviet blood donor sera from five different regions and 1,178 American donor sera from six different regions were tested in the USA. Among the Soviet donors, 450 (45%) had some marker of exposure to the hepatitis B virus; while among the American donors, 94 (8%) did. Of the Soviet donors 848 (85%) were positive for anti-HAV, compared with 403 (34%) of the American donors. For 1,977 serum samples that were evaluated in both countries for HBsAg, techniques in the USSR identified 36 HBsAg-positive samples, while the technique in the USA found 38 HBsAg-positive samples; however, only 24 were judged to be HBsAg-positive by assays in both countries. Testing of these same 1,977 sera for anti-HBs revealed that the radioimmunoassay used in the USA identified many more antibody-positive donors than the immuno-autoradiography technique used in the Soviet Union. When a portion of the sera were tested by similar radioimmunoassay techniques in each country, there was comparability of results for anti-HBs, as well as for anti-HAV, and anti-HBc. The results permit calculation of age and sex prevalence of hepatitis B and hepatitis A serologic markers for blood donors within and between each country. They also allow comparison, on the same sera, of test methodologies in use in the Soviet Union and in the United States.     

Cadaver donor discards secondary to serology

The use of cadaveric skin has made a major impact in the survival of patients experiencing major thermal injury. However, the availability of cadaveric skin is often limited by potentially pathogenic organisms. Very little data exists as to why cadaveric skin from donors who have been previously screened was discarded. From March 1994 to March 1996, 813 donors were referred to our tissue bank. All donors were reviewed for the cause of death, history and physical, and social history. One hundred fifty-three donors screened were discarded. Sixty-one donors of this group were discarded because of positive serologies. The following are the percentages of the specific positive serologies: hepatitis B core antibody, 52.3%; hepatitis B surface antigen, 18.1%; hepatitis C virus antibody, 14.3%; human immunodeficiency virus antibody, 4.9%; human T lymphocyte virus antibody, 4.9% and syphilis, 5.5%. Retrospectively, all donor screening questionnaires were reviewed for possible indicators in relation to positive serologic testing. Current screening methods, although excellent in social screening, still fail to identify a significant number of donors who may have positive serologies because of hepatitis, human immunodeficiency virus, human T lymphocyte virus, or syphilis. As the field of tissue banking continues to evolve, the focus will need to be directed toward better screening mechanisms in order to decrease our current discard rates after donors have been approved through the screening process.     

Epidemiology of hepatitis B in Canadian blood donors

BACKGROUND: The residual risk of hepatitis B is higher than for other markers such as human immunodeficiency virus and hepatitis C virus in nonendemic countries. Evaluating the potential for further risk reduction requires a better understanding of the relationship between donor selection criteria, immigration from endemic countries, and public health vaccination strategies. STUDY DESIGN AND METHODS: Age and sex trends of hepatitis B surface antigen (HBsAg)‐positive donors from 1997 to 2006 were analyzed using a Poisson model. All HBsAg‐positive donors in 2005/2006 plus four matched control donors for every HBsAg‐positive donor who participated were invited to participate in a risk factor interview and predictors of HBsAg positivity identified by logistic regression. A survey of 40,000 donors who did not react for all markers asked about vaccination history and country of birth. RESULTS: Most HBsAg‐positive donations were from first‐time donors (86%), have been decreasing in donors under the age of 30 (p < 0.01), and were correlated with geographic regions with more donors from higher‐prevalence countries (p < 0001). Birth in a higher‐prevalence country predicted HBsAg positivity (p < 0.01). Fifty‐six percent of donors reported being vaccinated for hepatitis including approximately 80 percent of donors under age 30 who reported being vaccinated as part of regular school programs. CONCLUSION: HBsAg‐positive donations are decreasing in donors under age 30, those most frequently vaccinated through provincial vaccination programs. HBsAg‐positive donations largely reflect immigration from high‐prevalence countries without other deferrable risk factors, mainly chronic cases that will be detected by current testing. Furthermore, risk of incident infections should decrease with increasing vaccination rates in donors, especially the younger cohort now receiving universal vaccination.     

Potential increased risk of virus transmission due to exclusion of older donors because of concern over Creutzfeldt-Jakob disease. The National Heart, Lung, and Blood Institute Retrovirus Epidemiology Donor Study

BACKGROUND: Concern over the theoretical possibility of disease transmission via blood from donors who develop Creutzfeldt-Jakob disease has led to proposals to exclude older individuals from donating plasma for further manufacture into pooled plasma donations. The impact of extending this age-deferral policy to blood donors was examined with respect to the risk for known transmissible viruses. STUDY DESIGN AND METHODS: Demographic characteristics and confirmed prevalence rates (/10(5) first-time donations) and incidence rates (/10(5) person-years for repeat donors) for viral markers were compared for donors < 50 years old (n = 1,259,805 [85%]) and > or = 50 years old (n = 219,856 [15%]) and for donors < 60 years old (n = 1,409,176 [95%]) and > or = 60 years old (n = 70,485 [5%]). Incidence rates were combined with infectious window-period estimates for each virus, to calculate the risk of virus transmission per 10(6) donations. RESULTS: Unadjusted prevalence rates were significantly greater for younger than for older donor groups for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), and hepatitis C virus (HCV) (p < or = 0.05). Incidence rates (and transmission risk estimates) for HBsAg were significantly higher in the < 50 donor group than in the > or = 50 group (p < or = 0.05), and those for HIV, human T-lymphotropic virus, and HCV were not significantly higher (p > 0.05). Blanket removal of donors over the age of 50 would potentially lead to the following significant increases in the risk of infected units: HIV, 12 percent; HCV, 21 percent; and hepatitis B virus (HBsAg), 22 percent. CONCLUSION: Removal of donors over the age of 60 would not significantly affect the risk of infected units. Deferral of donors > or = 50 years of age from whole-blood donations for unfounded concerns about Creutzfeldt-Jakob disease could have adverse effects on both blood availability and safety.     

Prevalence of hepatitis B virus and hepatitis C virus among blood donors at a tertiary care hospital in India: a five‐year study

BACKGROUND: Hepatitis B virus (HBV) and hepatitis C virus (HCV) are important transfusion‐transmissible infections. This study was performed to assess the prevalence of HBV and HCV seropositivity among blood donors at a tertiary care hospital–based blood bank in India. STUDY DESIGN AND METHODS: The blood donation records over 5 years (2005‐2009) were reviewed, retrospectively, for the prevalence and yearly trends of HBV and HCV seropositivity. RESULTS: A total of 94,716 donations were received. The overall number of HBV‐seropositive donations was 1353 and that for HCV was 537, with the prevalence rates of 1.43% for hepatitis B surface antigen (HBsAg) and 0.57% for HCV. The seropositivity rate was higher in the replacement donors compared to the voluntary donors. The annual rates showed decreasing trends in case of HBsAg, but in case of HCV, there was a linear increase. CONCLUSIONS: Our study raises serious concerns regarding the HBV and HCV prevalence in our country. Although HBV showed decreasing trends, it cannot be relied upon because the donors were screened only for HBsAg. HCV is clearly on the rise. Stringent measures need to be taken on urgent basis including dissemination of information, strict screening of blood, inclusion of antibody to hepatitis B core antigen and other sensitive markers to the screening protocol, and better donor recruitment.     

Performance of an algorithm for the reentry of volunteer blood donors deferred due to false-positive test results for antibody to hepatitis B core antigen

BACKGROUND: Blood donor testing for antibody to hepatitis B core antigen (anti‐HBc) has been used in the United States for more than 20 years as a surrogate to prevent transmission by transfusion of non‐A,non‐B hepatitis, as a human immunodeficiency virus surrogate, and to reduce transmission of hepatitis B virus (HBV). Nonspecific anti‐HBc assays have caused deferral of hundreds of thousands of otherwise qualified donors. A more specific anti‐HBc test and a sensitive HBV DNA test should permit donor reentry after false‐positive anti‐HBc. STUDY DESIGN AND METHODS: A total of 1324 otherwise eligible volunteer donors, deferred for anti‐HBc reactivity on more than one occasion, were recruited from four collection facilities. They were tested using a licensed, more specific anti‐HBc test, a licensed hepatitis B surface antigen (HBsAg) test, and a licensed HBV DNA assay with a 95 percent limit of detection of not more than 10 copies per mL. RESULTS: From 11 to 32 percent of donors contacted by participating sites entered the study. Overall, 488 (37%) of the donors were negative on the more specific anti‐HBc test. The proportion of putative false‐positive samples varied according to the test responsible for the original deferral. A single donor, negative for the presence of anti‐HBc and HBsAg, was positive for the presence of HBV DNA in one of three replicates. Repeat testing of this donor 10 months later was negative for the presence of all markers of HBV infection, and the donor had a history of HBV vaccination with documented postimmunization anti‐HBs seroconversion 10 years before her anti‐HBc deferral, and was considered HBV DNA false positive. CONCLUSION: These data support reentry of donors with false‐positive anti‐HBc results on the relatively nonspecific assays that have been in use in the United States for more than 20 years.     

Impact of a policy to permit the return of donors repeat-reactive to the Abbott PRISM antibody to hepatitis B core antigen assay

BACKGROUND: The expected donor loss from recent implementation of antibody to hepatitis B core antigen (anti-HBc) testing in Canada was uncertain but potentially significant based on US experience. To reduce donor loss from false-reactive tests, repeat-reactive donors without other evidence of infection were eligible to return. The aim was to evaluate the impact of anti-HBc testing on donor loss and to evaluate the effectiveness of this policy.
STUDY DESIGN AND METHODS: For each donor in the first year of implementation (April 9, 2005-April 8, 2006) repeat-reactive for the presence of anti-HBc only but eligible to return (screening test for hepatitis B surface antigen–negative, plus not reactive to antibody to hepatitis B surface antigen [anti-HBs] and hepatitis B virus [HBV] DNA supplemental tests), 10 matched donors not reactive to the anti-HBc assay were selected. Return rates over 2 years were compared using conditional logistic regression. Testing outcomes were tabulated.
RESULTS: Over the first year of testing, 412,236 donors (951,423 donations) were tested for anti-HBc, and 4,489 donors were repeat-reactive (1.3% of first-time donors, 1.0% of repeat donors). Of these 85.6 percent were also reactive for the presence of anti-HBs and/or HBV DNA supplemental tests leaving less than 15 percent eligible to return, of whom 73 percent returned (vs. 90% of controls, p < 0.001). Of the 300 anti-HBc repeat-reactive returning donors, 74 percent were anti-HBc repeat-reactive again (thus permanently deferred), 19 percent were deferred for other reasons versus 14 percent of controls (p < 0.05), and 7 percent (21 donors) did not react and were eligible to continue donating.
CONCLUSION: Most donors repeat-reactive for the presence of anti-HBc likely have past exposure to HBV. If eligible, most are willing to return, but likely to test anti-HBc repeat-reactive again.     

Prevalence of serologic markers for hepatitis B and C viruses in Brazilian blood donors and incidence and residual risk of transfusion transmission of hepatitis C virus

BACKGROUND: We evaluate the current prevalence of serologic markers for hepatitis B virus (HBV) and hepatitis C virus (HCV) in blood donors and estimated HCV incidence and residual transfusion‐transmitted risk at three large Brazilian blood centers. STUDY DESIGN AND METHODS: Data on whole blood and platelet donations were collected from January through December 2007, analyzed by center; donor type; age; sex; donation status; and serologic results for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti‐HBc), and anti‐HCV. HBV and HCV prevalence rates were calculated for all first‐time donations. HCV incidence was derived including interdonation intervals that preceded first repeat donations given during the study, and HCV residual risk was estimated for transfusions derived from repeat donors. RESULTS: There were 307,354 donations in 2007. Overall prevalence of concordant HBsAg and anti‐HBc reactivity was 289 per 100,000 donations and of anti‐HCV confirmed reactivity 191 per 100,000 donations. There were significant associations between older age and hepatitis markers, especially for HCV. HCV incidence was 3.11 (95% confidence interval, 0.77‐7.03) per 100,000 person‐years, and residual risk of HCV window‐phase infections was estimated at 5.0 per million units transfused. CONCLUSION: Improvement in donor selection, socioeconomic conditions, and preventive measures, implemented over time, may have helped to decrease prevalence of HBV and HCV, relative to previous reports. Incidence and residual risk of HCV are also diminishing. Ongoing monitoring of HBV and HCV markers among Brazilian blood donors should help guide improved recruitment procedures, donor selection, laboratory screening, and counseling strategies.     

Prevalence of antibodies to hepatitis B core antigen and occult hepatitis B virus infections in Korean blood donors

BACKGROUND: This study was performed to determine the prevalence of antibodies to hepatitis B core antigen (anti‐HBc) among Korean blood donors and frequencies of hepatitis B virus (HBV) DNA and antibodies to hepatitis B surface antigen (anti‐HBs) in anti‐HBc–positive donors. STUDY DESIGN AND METHODS: A total of 12,461 consenting blood donors were consecutively enrolled from Korean Red Cross Blood Services from April to October 2008. All of the donors were screened for anti‐HBc with an electrochemiluminescence immunoassay. Repeat‐reactive anti‐HBc–positive donors were assayed for anti‐HBs and for HBV DNA using a multiplex test (Cobas TaqScreen, Roche Molecular Systems) on individual donation. RESULTS: Of the 12,461 donors, 1682 (13.5%) were reactive for anti‐HBc. Among different age groups, there was a steady increase in the anti‐HBc–positive rate, ranging from 2.0% in the age group of less than 20 years to 80.0% in the age group of 60 years and older (p < 0.0001). Of the anti‐HBc–positive donors, 1523 (90.5%) were anti‐HBs positive. HBV DNA was detected in two donors who were anti‐HBc positive and hepatitis B surface antigen negative. The prevalence of occult HBV infection was 0.016%, and the HBV nucleic acid test (NAT) yield was 1 in 838 (0.12%). CONCLUSION: This study helps to determine the current status of hepatitis B infection and the prevalence of occult HBV infection in the blood donor population in Korea. We estimate that in Korea, up to 161 units per million donated units from blood donors may contain HBV DNA. Although the potential infectivity of these units has been debated upon, the HBV NAT assay could prevent certain transfusion‐transmitted HBV infections.     

Antibody to hepatitis B core antigen in blood donors with a history of hepatitis

Sera and questionnaires from 3,230 prospective U.S. volunteer blood donors were obtained in an earlier study to determine the prevalence of serologic markers of hepatitis B virus (HBV) and hepatitis A virus (HAV) among prospective blood donors with or without a history of either hepatitis or blood transfusion. These sera were reevaluated using a radioimmunoassay for antibody to hepatitis B core antigen (anti- HBc). Anti-HBc in the absence of hepatitis B surface antigen (HBsAg) or its antibody (anti-HBs) was detected in 30 of 1,151 (2.6%) prospective donors with a history of hepatitis, compared to four of 1,086 (0.4%) with no history of hepatitis (p less than 0.001). Although end-point dilution titers of anti-HBc greater than or equal to 1:100 and the presence of IgM anti-HBc were more frequently detected among donors with a history of hepatitis than among donors with no history of hepatitis, the difference was not statistically significant. Unlike a history of hepatitis, a history of transfusion or a history of exposure to persons with hepatitis had no significant association with the detection of anti-HBc in the absence of other HBV serologic markers.     

New hepatitis B virus mutant form in a blood donor that is undetectable in several hepatitis B surface antigen screening assays

BACKGROUND: Envelope mutant forms of hepatitis B virus (HBV), impairing HBV antibody recognition, have been reported with mutations in single or multiple sites of the hepatitis B surface antigen (HBsAg) group- specific "a" determinant. Blood donors infected with such an HBsAg mutant form of HBV may escape detection by HBsAg screening assays and therefore may affect the safety of the blood supply. CASE REPORT: A repeat blood donor became HBsAg-reactive in an enzyme immunoassay. Confirmatory testing yielded negative results for HBsAg in a radioimmunoassay and in four enzyme immunoassays used in blood donor screening. The specificity of the HBsAg reactivity in the first enzyme immunoassay was confirmed by HBsAg neutralization with antibody to HBsAg. Additional HBV confirmatory test results were positive for antibody to hepatitis B core antigen and antibody to hepatitis B e antigen; negative for antibody to HBsAg and for hepatitis B e antigen; and positive for HBV DNA. DNA sequence analysis of the "a" determinant region of HBsAg revealed amino acid substitutions from Q (Gln) to R (Arg) at codon 129 and from M (Met) to T (Thr) at codon 133. CONCLUSION: This case illustrates the presence of HBsAg mutant forms of HBV in a West European blood donor population that were undetected by several HBsAg screening assays. Adaptation of HBsAg screening is indicated to overcome deficiencies in sensitivity in detecting HBsAg mutant forms of HBV. Screening for antibody to hepatitis B core antigen or HBV DNA may also detect blood donors infected with HBsAg mutant forms of HBV     

Feasibility and usefulness of an efficient anti-HBc screening programme in blood donors

SUMMARY. Post-transfusion hepatitis B remains a risk for recipients of hepatitis B surface antigen (HBsAg) screened blood. Anti-hepatitis B core antibody (anti-HBc) screening may help reduce this risk. To evaluate its usefulness, 9,238 East Anglian blood donors were screened for anti-HBc. Those with isolated anti-HBc were identified with two confirmatory anti-HBc and anti-HB surface antibody (anti-HBs) assays. The prevalence of anti-HBc reactions in screening and confirmatory assays was 1.29% and 0.35%, respectively. The level of reactivity was significantly higher when two anti-HBc assays gave concordant results or, being concordant, were anti-HBs positive. All isolated anti-HBc-positive units (0.04%) were negative for additional HBV markers including DNA tested with nested polymerase chain reaction (PCR).
A 0.31% prevalence of past HBV infection was found in this population, all carrying both anti-HBc and anti-HBs antibody, most above the protective level (0.IU/ml).
The proposed screening schemes would limit the number of deferred donors and discarded units and keep the testing time within the remit of routine blood banking practices for an additional cost of approximately £1 per unit. However, no evidence was found in this donor population to suggest that anti-HBc screening would significantly reduce the incidence of post-transfusion hepatitis B.     

Anti-hepatits B core antigen testing, viral markers, and occult hepatitis B virus infection in Pakistani blood donors: implications for transfusion practice

BACKGROUND: The purpose of this study was to determine the seroprevalence of anti-hepatitis B core antigen (HBc) and the impact of its testing along with other markers of hepatitis B, hepatitis B virus (HBV) DNA, hepatitis C virus antibody (anti-HCV), and syphilis in Pakistani blood donors. STUDY DESIGN AND METHODS: The study design was cross-sectional. A total of 966 donors were selected randomly for testing of anti-HBc and HBV markers, including HBV DNA, of 94,177 blood donors who were routinely screened for hepatitis B surface antigen (HBsAg), anti-HCV, human immunodeficiency virus antibody (anti-HIV), Treponema pallidum hemagglutination assay (TPHA), and malarial parasites from 2003 to October 2005. RESULTS: The seroprevalence of various infectious markers was as follows: HBsAg, 2.16 percent; anti-HCV, 4.16 percent; anti-HIV, 0.004 percent; TPHA, 0.75 percent; and malaria, 0.002 percent. Anti-HBc prevalence in HBsAg-negative, HBV DNA-negative blood donors was 167 of 966 (17.28%), with 76 percent demonstrating anti-HBs positivity. Younger donors with mean age of 25 years were exposed to HBV to a lesser extent compared to those with a mean age of 29 years. Anti-HBc positivity was significantly higher in anti-HCV-reactive individuals. HBV DNA was detectable in 5 blood donors who were HBsAg-, anti-HBc-positive and were categorized as having occult HBV infection. CONCLUSIONS: The study shows that more than 17 percent of healthy, young blood donors in Pakistan are already exposed to HBV, with two-thirds showing anti-HBs levels of greater than 100 mIU per mL. One in 200 blood donors who are HBsAg-, anti-HBc-positive, however, have occult HBV infection, with likelihood of transmission of hepatitis B in recipients of blood components derived from them. HBsAg-negative individuals who are anti-HBc-negative and those who are anti-HBc-positive, anti-HBs-positive, and HBV DNA-negative should be selected as regular blood donors to minimize transmission due to occult hepatitis B infection.