乙型肝炎血清学标志间非特异性交叉反应的研究

为证实乙型肝炎（乙肝）血清学标志酶联免疫吸附试验（ＥＬＩＳＡ）试剂中五种抗原抗体反应的特异性，采用排列组合的交叉反应方式，对Ａｂｂｏｔｔ和部分国产试剂盒中五种抗原抗体进行交叉反应研究，结果表明：所有生产商的乙肝血清学标志ＥＬＩＳＡ试剂盒中，酶标记抗－ＨＢｅ和包被的ＨＢｃＡｇ都存在交叉反应，大部分生产商的抗－ＨＢｃ与ＨＢｅＡｇ也存在交叉反应。实验证实抗－ＨＢｅ和抗－ＨＢｃ之间存在非恃异性交叉反应。考虑临床上抗－ＨＢｃ和抗－ＨＢｅ检测阳性率较高，非特异性交叉反应可能是重要原因。     

HCV antibodies in Hungarian blood donations. Experiences collected by ELISA tests, immunoblot assays and polymerase chain reaction and protocols for donor management

SUMMARY. Routine screening of Hungarian blood donors for anti-HCV commenced in the second half of 1992. Before this, five available anti-HCV ELISA kits were compared in pilot studies. In the first series, 831 random donor samples were tested by one of the tests and the 12 (1.4%) reactives found were retested by the other four. Six of the reactives were positive in all ELISA. In the second series, 325 samples from donors with elevated transaminase levels were tested by all five kits. Forty-four were found to be reactive by one or more of the tests and 32 (10%) were positive in all five assays. Samples concordantly reactive in the ELISA were positive in second or third generation recombinant immunoblot assay (RIBA 2 or RIBA 3); those that gave discordant results were indeterminate or negative. Eleven concordantly reactive samples from the second series were HCV RNA positive by polymerase chain reaction (PCR). In the first period of screening with Abbott ELISA 2 a repeat-reactivity rate of 0.98% was observed in 171,106 samples tested. Reactives were retested for supplementary testing by Wellcozyme anti-HCV. Donors reactive in both tests and strongly reactive (ELISA ratio ( ER ) = optical density/cut off 2.5) in either of them were permanently deferred. Those negative in the supplementary ELISA or weakly reactive (1.0<2.5) in both tests were subjected to RIBA 2. On the basis of RIBA, positive donors were permanently deferred, indeterminates were excluded for 1 year and negatives were readmitted. In 1992, 1,347 supplementary tests were completed; 824 (61%) of the respective donors were permanently deferred, 218 (16%) were deferred for 1 year and 305 (23%) were readmitted.     

Anti-HTLV-III testing of blood donors: reproducibility and confirmability of commercial test kits

Since 2% of the cases of Acquired Immune Deficiency Syndrome (AIDS) have been attributed to transfusions of blood and blood products, licensed tests to detect antibody to the human T-lymphotropic virus type III (anti-HTLV-III) have been put into practice to reduce the risk of transfusion associated AIDS. Two commercial ELISA kits (Abbott and ENI) were used to test for anti-HTLV-III in 100 coded samples from individuals with AIDS, at high risk for AIDS, or with low risk for AIDS and in 1280 unlinked blood donor serums. From the 100 coded samples, both Abbott and ENI tests identified 51 of 52 coded samples with anti-HTLV-III which were confirmable with Western blot analysis. Initial testing of the donor serums by Abbott's test revealed 20 reactives, of which 5 were repeatably reactive; initial testing by ENI's test revealed 25 reactives, of which 14 were repeatably reactive. However, only 3 donor serums were repeatably reactive by both test kits, out of 17 repeatable reactive by either, and no ELISA positive samples were confirmed by Western blot or IFA. Before a blood donor is notified of "anti-HTLV-III reactivity", tests demonstrating this should be both reproducible and confirmable by at least one additional test.     

四川地区供血浆人群隐匿性乙型肝炎病毒感染的研究

目的了解四川地区供血浆人群隐匿性乙型肝炎病毒感染(OBI)情况,分析现行标准下原料血浆的HBV残余风险。方法采用实时荧光PCR和ELISA法,对四川地区10个单采血浆站2007年7月～2009年7月筛查合格的56 620名次供浆者的135 542份原料血浆标本作HBV NAT和HBsAg同步筛查,对筛查阳性的标本以进口试剂复核、作中和试验及HBV DNA定量测定,并对阳性血浆的供血浆者追踪分析,确认OBI标本。结果共检出HBV DNA阳性12份(9人),四川地区原料血浆HBV DNA检出率为0.008 9%(12/135 542);HBV DNA载量均<1 000 IU/ml;采用国产ELISA试剂检测该12份标本HBsAg均为阴性,而用进口试剂检测并经中和试验确认了其中5份(3人)为HBsAg阳性,其余7份(6人)为OBI血浆,血清学模式均为HBsAg-/HBeAg-/HBcAb+;对供血浆者2～9个月的追踪分析显示ELISA和NAT检测结果无变化,与筛查结果一致。结论 HBsAg阴性供血浆人群中存在OBI感染者,四川供浆人群中OBI感染率为0.010 6%(6/56 620),低于现有报道的我国无偿献血者的OBI感染率;按照现行要求采用ELISA法检测原料血浆,灵敏度较低的国产试剂检测HBsAg的残余风险(0.0089%)高于进口试剂(0.005 2%)。增加HBV NAT能有效降低原料血浆OBI的漏检风险。     

Relationship between antibody to hepatitis B core antigen and retroviral infections in blood from volunteer donors

Background: The value of the test for antibody to hepatitis B core antigen (anti-HBc) as a surrogate screening assay in the time before sensitive, virus-specific screening tests were available has been well established. There is significant debate, however about the residual value of anti-HBc screening after the implementation of human immunodeficiency virus (HIV)-, human T-lymphotrophic virus (HTLV)-, and hepatitis C virus (HCV)-specific assays and, in particular, about its utility as a lifestyle marker to identify persons at risk for retrovirus infections. Study Design and Methods: Screening tests for antibodies to HIV, HTLV, and HBc, as well as confirmatory or supplemental test results for anti-HIV and anti-HTLV, were obtained from approximately 2.8 million donations collected from 1991 through 1993 by five blood centers within the United States. The sensitivity, positive predictive value, and relative prevalence of anti-HBc for each retrovirus were calculated and compared among demographic subgroups. Results: The overall relationship between anti-HBc and anti-HIV was similar to that between anti-HBc and anti-HTLV. When calculated from the measured endpoint of the prevalence of anti-HIV-positive and anti- HTLV-positive donations, the sensitivities were 31.1 and 26.2 percent, the positive predictive values were 0.18 and 0.21 percent, and the relative prevalences were 30.1 and 23.8, respectively. Among 27 anti- HIV-seroconverting donors and 9 anti-HTLV-seroconverting donors, the sensitivities were 7.4 percent (95% CI: 0.9–24.3%) and 0 percent (95% CI: 0.0–28.3%), respectively. It was estimated that for each HIV- infected window-period donation detected by anti-HBc, from 19,000 to 81,000 HIV-noninfected donations are discarded. Similarly, more than 33,000 HTLV-noninfected donations are likely to be discarded for each HTLV-infected donation detected by anti-HBc. Conclusion: Although anti- HBc-reactive donations are more likely to be seropositive for a retrovirus than are anti-HBc-nonreactive donations, the low positive predictive value limits the test's effectiveness. If the anti-HBc test is retained in the blood donor setting, efforts should be focused on reducing the number of false-positive results.     

Infectivity of blood components with low hepatitis B virus DNA levels identified in a lookback program

BACKGROUND: Japanese Red Cross (JRC) blood centers implemented anti-hepatitis B core antigen (HBc) screening in 1989 and 50-minipool (MP)-nucleic acid testing (NAT) in 2000. A systematic lookback study has been conducted to determine the hepatitis B virus (HBV) transmission risk of donations drawn in the pre-hepatitis B surface antigen (HBsAg) and/or MP-NAT window phase and by donors with occult HBV infection. STUDY DESIGN AND METHODS: JRC blood centers have been storing aliquots of every blood donation since 1996. On the basis of the complete repository tube archives, all donations from repeat donors received from 1997 to 2004 were subjected to a lookback study. When repeat donors turned positive for HBV viral marker(s), repository tubes from their previous donations were tested for HBV with individual-donation (ID)-NAT. The frequency of ID-NAT-only-positive donations and the HBV transmission risk by the transfusion of those components were investigated. RESULTS: HBV ID-NAT was performed on 15,721 repository tubes, and 158 tubes (1.01%) were found positive for the presence of HBV DNA. Of these 158 ID-NAT-only-positive donations, 95 (60%) were derived from carriers with low anti-HBc titers. Of 63 patients transfused with ID-NAT-only-positive components, 12 (19%) proved to be infected with HBV. Only 1 of 33 components with low anti-HBc titers could be identified as infectious, whereas 11 of 22 anti-HBc-negative components proved to be infectious. None of the 16 identified hepatitis B surface antibody-positive components showed serologic evidence of infection. CONCLUSION: The clinically observed HBV infection risk caused by blood components from occult HBV carriers with low anti-HBc titers who slip through the JRC screening system is more than 10-fold lower than the transmission risk by donations in the pre-HBsAg and/or MP-NAT window phase.     

Retrospective follow-up of recipients and donors of blood donations reactive for anti-HBc or for single HCV antibodies

A retrospective study was undertaken to investigate the infectivity of blood donations that were HCV RIBA indeterminate or reactive for 'anti-HBc only'. Samples from 6032 blood donations were tested for anti-HBc; 17 of them were positive for anti-HBc but were negative when tested for anti-HBs. None of the recipients of the red cells from these donations, when tested 9 months after transfusion, had evidence of HBV infection. Samples from 3000 blood donations were tested for HCV antibodies using RIBA-3; 53 had single lines. Samples taken 9 months after transfusion from the recipients of the red cells from these donations were tested for evidence of infection with hepatitis C, and all were negative.     

Hepatitis B virus DNA-positive, hepatitis B surface antigen-negative blood donations intercepted by anti-hepatitis B core antigen testing: the Canadian Blood Services experience

BACKGROUND: The benefit of introducing anti-hepatitis B core antigen (HBc) screening for intercepting potentially infectious donations missed by hepatitis B surface antigen (HBsAg) screening in Canada was studied. STUDY DESIGN AND METHODS: Anti-HBc testing of all donations was implemented in April 2005, along with antibody to hepatitis B surface antigen (anti-HBs) and hepatitis B virus (HBV) DNA supplemental testing of anti-HBc repeat-reactive, HBsAg-negative donations. The proportion of potentially infectious donations intercepted by anti-HBc over the initial 18 months of testing was calculated based on three assumptions relating infectivity of HBV DNA-positive units to anti-HBs levels. Lookback was conducted for all DNA-positive donations. RESULTS: Of 493,344 donors, 5,585 (1.13%) were repeat-reactive for the presence of anti-HBc, with 29 (0.52%) being HBV DNA-positive and HBsAg-negative. The proportion of potentially infectious donations intercepted by anti-HBc screening was 1 in 17,800 if all HBV DNA-positive donations were infectious, 1 in 26,900 if infectivity was limited to donations with an anti-HBs level of not more than 100 mIU per mL, and 1 in 69,300 if only donations with undetectable anti-HBs were infectious. For 279 components in the lookback study, no traced recipients were HBsAg-positive and 7 recipients were anti-HBc-reactive in association with 4 donors, 3 of whom had an anti-HBs level of more than 100 mIU per mL and 1 of whom had a level of 61 mIU per mL. CONCLUSION: Implementation of anti-HBc screening reduced the risk of transfusing potentially infectious units by at least as much as had been expected based on the literature. The lookback did not provide proof of transfusion transmission of HBV from HBV DNA-positive, anti-HBc-reactive, HBsAg-negative donors but it did not establish lack of transmission either.     

American Red Cross experience with routine testing for hepatitis B core antibody

The implementation of routine testing of blood donations for hepatitis B core antibody (anti-HBc) has allowed the characterization of the performance of the test in a large number of samples from apparently healthy individuals. This study reports the experience of the American Red Cross in testing 2.3 million donors for anti-HBc. The test protocol reproducibly identified a distinct population of donors. The anti-HBc-positive rate varied by region of the continental United States and by the time of year. In a case-control study, 85 percent of subsequent donations from anti-HBc-positive donors were anti-HBc positive. The predictions made in an earlier pilot study regarding the performance and impact of the test were borne out.     

Hepatitis B core antibody screening of voluntary blood donors: an extended pilot study using a modified passive haemagglutination assay

Summary. Screening for hepatitis B surface antigen (HBsAg), even by the most sensitive techniques, fails to detect all carriers of the hepatitis B virus (HBV). The presence of hepatitis B core antibody (anti-HBc) in the absence of HBsAg is a common finding in donors implicated in cases of post-transfusion hepatitis B (PTHB), and viral DNA may also be demonstrated in many of these individuals. An extended pilot study of routine screening of all donations for anti-HBc in addition to HBsAg was introduced into the Mersey and North Wales Regional Transfusion Service in November 1991 to improve surveillance for carriers of HBV. In order to reduce costs a modified passive haemagglutination assay was evaluated and found to have a sensitivity of 99% and specificity of 98% compared with a conventional assay. In the first 6 months 60 530 donations were tested and 12 (0–02%) were found to have anti-HBc in the absence of HBsAg or adequate antibodies to HBsAg (anti-HBs). These sera will later be submitted for polymerase chain reaction (PCR) testing in order to determine their infectivity or otherwise by the detection HBV DNA sequences.     

Anti-HBc screening in Egyptian blood donors reduces the risk of hepatitis B virus transmission

summary .  Occult hepatitis B virus (HBV) in blood donors is considered as a potential risk for transmission of HBV infection. The aim of this study was to determine the prevalence of anti-hepatitis B core antibody (anti-HBC) positivity in Egyptian blood donations as well as to estimate the frequency of HBV-DNA in anti-HBc-positive donations. The study included 760 Egyptian healthy blood donors, representing 26 different Egyptian governorates screened according to routine practice for the presence of hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies (Abs), HIV-1/2 Abs and Treponema Abs. The accepted blood units for donation were tested for the presence of total anti-HBc Abs by two tests. Positive units for anti-HBc were further tested for HBV-DNA by polymerase chain reaction. According to routine screening, a total of 48/760 units (6·3%) were rejected [38 (5%) HCV-Ab-positive units, 9 (1·18%) HbsAg-positive units and 1 (0·13%) Treponema-Ab-positive unit]. Among the accepted blood units for donation, prevalence of anti-HBc was 78/712 units (10·96%). HBV-DNA was detected in 9/78 (11·54%) of the anti-HBc-positive units, and thus, occult HBV infection was detected in 9/712 (1·26%) of the accepted blood donations. Implementing anti-HBc test to the routine assay for the forthcoming two decades would certainly eliminate possible HBV-infected units. Rejection of these units will be beneficial to decrease the risk of HBV transmission with its potential consequences particularly in immunocompromised recipients.     

Value and cost-effectiveness of screening blood donors for antibody to hepatitis B core antigen as a way of detecting window-phase human immunodeficiency virus type 1 infections. The HIV Blood Donor Study Group

BACKGROUND: The value of screening donors for antibody to hepatitis B core antigen (anti-HBc) for the prevention of posttransfusion hepatitis has declined markedly. However, anti-HBc screening may still be useful as a surrogate marker for the window period (WP) of human immunodeficiency virus type 1 (HIV-1) infection. STUDY DESIGN AND METHODS: First, the relationship between anti-HBc reactivity and HIV-1 WP infections was examined among 225 donors who had seroconverted to anti-HIV-1 positivity between 1987 and 1990. In addition, data from 1654 HIV-1 seropositive donors were analyzed to characterize the relationship among anti-HBc reactivity, donor demographics, and HIV-1- related risk factors. The yield and cost-effectiveness of anti-HBc for HIV-1 prevention were then projected on the basis of a published decision analysis model. RESULTS: Forty (18%) of 225 HIV-1- seroconverting donors tested anti-HBc-reactive on the donation preceding anti-HIV-1 seroconversion; in contrast, 341 (34%) of 1014 HIV- 1-seropositive donors interviewed tested anti-HBc-reactive (chi-square test; p < 0.001). Anti-HBc reactivity was more common among HIV-1- seropositive donors reporting male-to-male sexual contact (169/360, 47%) and injection drug use (44/83, 53%) than among those with heterosexual contacts known to be HIV-1-positive (31/190, 16%) or transfusion exposure (3/21, 14%) or among females with no identified risk factors (21/124, 17%). The estimates of 18 to 34 percent sensitivity for anti-HBc in detecting HIV-1 WP donations and a current rate of 1 in 676,000 HIV-1 WP donations (after p24 antigen screening) suggest that continued use of anti-HBc screening could result in the transfusion of 5 to 12 fewer HIV-1-infected units per year in the United States, which would add 19 to 48 quality-adjusted years of life for the 3.5 million annual transfusion recipients at a cost of $992,020 to $2,345,000 per quality-adjusted life-year saved. CONCLUSION: The low yield and very poor cost-effectiveness of anti-HBc screening indicate that this test is not an effective screening test for HIV-1 WP donations.     

Blood donation screening for hepatitis B virus markers in the era of nucleic acid testing: are all tests of value?

BACKGROUND: The American Red Cross implemented hepatitis B virus (HBV) minipool (MP)‐nucleic acid testing (NAT) in June 2009, in addition to existing tests for hepatitis B surface antigen (HBsAg) and antibodies to hepatitis B core antigen (anti‐HBc). The value of all three tests was evaluated. STUDY DESIGN AND METHODS: HBsAg, anti‐HBc, and HBV DNA (Ultrio MP‐NAT, Gen‐Probe/Novartis) donation results were analyzed during a 12‐month period (July 1, 2009‐June 30, 2010). Additional testing by individual‐donation (ID) polymerase chain reaction (PCR) to confirm donor infection was performed when any HBV screening test was reactive or positive, except in the case of HBsAg neutralization‐positive, anti‐HBc–reactive samples. Numbers of blood donations identified as reactive or positive versus nonreactive or negative were compared. RESULTS: Of about 6.5 million donations, 699 were defined as from HBV‐infected donors, of which 64% (444) were reactive for all three markers. More than 99% (697) had reactivity to one or both serologic tests with 68% (477) showing reactivity by MP‐NAT. Only two donations were DNA‐positive, seronegative NAT‐yield donations (1 per 3.23 million), fewer than expected (p = 0.0075). Among MP‐NAT–reactive donors, only small numbers represented early infection (2 or 0.4% with negative serology and 10 or 2.1% who were HBsAg confirmed positive, anti‐HBc nonreactive). Of the 142 occult HBV‐infected donors, 85% were MP‐NAT nonreactive requiring ID‐PCR for detection (121 or 54.5% of all MP‐NAT nonreactives vs. 21 or 4.4% of all MP‐NAT reactives). CONCLUSIONS: The HBV DNA–positive yield rate from MP‐NAT was lower than expected, likely representing the rarity of such findings even in very large studies. With the implementation of HBV MP‐NAT, the value of maintaining anti‐HBc for the detection of low‐level HBV DNA–positive donors was confirmed; however, HBsAg screening showed no blood safety value.     

HBsAg阴性、HBV DNA阳性献血者病毒感染特征研究

目的了解上海地区献血人群中血清HBsAg阴性、HBV DNA阳性感染的流行率、病毒血清学和分子生物学特点。方法选取HBsAg阴性、核酸筛查确认为HBV DNA阳性的献血者血清标本,采用酶联免疫法（ELISA）检测病毒血清标志物抗-HBc和抗-HBs;PCR扩增HBV S区基因片段,对扩增后的产物进行测序分析后,将产物序列与Genbank中HBV序列进行Blast比对,获得标本HBV毒株的基因型;采用DNAMAN软件进行蛋白表达分析,确定标本毒株的血清型,并与Genbank中野生型HBV序列进行比较,获得S区基因编码蛋白突变情况。结果上海地区HBsAg阴性献血人群HBV DNA阳性感染率约为0.045%。18例HBsAg阴性、HBV DNA阳性标本血清病毒载量均低于200IU/ml,且大部分低于20IU/ml;其中14例（77.8%）病毒血清标志物为抗-HBc和/或抗-HBs阳性。18例样本全部为B和C基因型,主要为adw和adr血清型。14例血清抗-HBc和/或抗-HBs阳性样本中,13例样本发生了S蛋白氨基酸突变,其中8例B基因型较多发生Q101K/H、M103T/I、F134L、D144A突变,5例C基因型较多发生S114T/A、T118K/R、K141T、S143T突变;4例血清阴性样本中,均未发生S区蛋白位点突变。结论上海地区献血者存在HBsAg阴性、HBV DNA阳性感染者,其血清病毒载量低,感染病毒全部为B和C基因型,主要为adw和adr血清型;其中大部分为隐匿性HBV感染,少数可能为窗口期感染;隐匿性HBV感染病毒多发生S蛋白氨基酸位点突变。     

Detection of HTLV-III antibodies using ELISA and the western blot

Three commercially available ELISA test kits were used for the detection of antibodies to HTLV-III, the cause of AIDS. Positive results were confirmed by means of the Western Blot. In the course of our routine diagnostic studies, a total of 112 infections with HTLV-III were found among persons in high-risk groups or in blood donors, of whom only 13 presented the clinical picture of AIDS. About 20% of all seropositive persons were intravenous drug addicts. Upon comparison of the ELISA kits of Abbott, Organon, and Sorin, no conclusive indication of a false negative result has been obtained to date with any test kit. Differences were, however, found as regards the number of repeatedly positive samples that could not be confirmed in the Western Blot. The highest rate of these false positive results was found with the Abbott-ELISA, followed by Sorin, while the Organon test did not yield a single false positive result. The lack of agreement in a certain percentage of the tested samples is probably caused by differences in the cut-off values of the various ELISAs used. This value is chosen in such a manner that false positive results are avoided, while even low levels of antibodies are still detected. Since there was no evidence of false negative results, all three kits are suitable for HTLV-III screening of sera. Our results show the need for confirmation of positive results with ELISA by means of the Western Blot.     

Evaluation of dengue NS1 antigen detection tests with acute sera from patients infected with dengue virus in Venezuela

The performances of 2 commercial enzyme-linked immunosorbent assay (ELISA) kits (PLATELIA™ Dengue NS1 AG and Dengue Early ELISA) and a rapid immunochromatography test (Dengue NS1 AG Strip) for detection of dengue NS1 protein were compared using a panel of 87 sera from viremic dengue patients, as well as 36 sera from patients with other acute febrile illnesses. PLATELIA™ was more sensitive and slightly less specific than Dengue Early ELISA (sensitivity, 71.3% versus 60.9%; specificity, 86.1% versus 94.3%, respectively). The strip test showed an overall sensitivity of 67.8% with a specificity of 94.4%. A lower sensitivity was observed with Dengue Early ELISA for dengue virus (DENV) type 4 (30%) and by the 3 tests for DENV type 2 (56.5%). The use of these kits allows for rapid and specific early diagnosis of dengue infection; however, their sensitivity for each serotype must be further evaluated to guarantee an accurate diagnosis, particularly in those regions where the 4 dengue serotypes are cocirculating.     

Comparison of assays for anti-HBc in blood donors

Testing for anti-HBc has been recommended for use as a paradoxical or surrogate marker of carriers of non-A, non-B hepatitis. Serial sampling on a pool of 35,600 donors was done and those donors found to be repeatedly reactive by EIA method were rested using RIA methodology. Of 1367 donors found to be repeatedly reactive by EIA method, only 984 were confirmed by RIA. Those found to be reactive by EIA only were allowed to donate blood again, with only three of them becoming positive by both EIA and RIA on subsequent donations. The majority of these donors (107 out of 151) reverted to EIA negative status. Therefore, the finding of a positive anti-HBc by EIA method that could not be repeated by RIA method is not an early reproducible sign of anti-HBc reactive status.     

Current tests for antibody to hepatitis b core antigen used to screen donors for non-A, non-B hepatitis are comparable to the original radioimmunoassay for hepatitis B core antigen

Prospective studies have shown a relationship between the transfusion of donor blood which is positive for antibodies to hepatitis B core antigen (anti-HBc) and an increased incidence of non-A, non-B hepatitis. The anti-HBc test was selected on the assumption that epidemiologic circumstances predisposing donors to hepatitis B infection also might favor exposure to non-A, non-B hepatitis. Current radioimmunoassays (RIA) and enzyme-linked immunoassays (EIA) for anti-HBc utilize hepatitis B core antigen (HBcAg) prepared by recombinant DNA technology, whereas the original RIA anti-HBc assay used HBcAg derived from hepatitis B virions. In the current study, 1329 sera were evaluated of which 23.3 percent were anti-HBc positive. The results indicate that sensitivity, specificity, and positive and negative predictive values of the current EIA and RIA tests for anti-HBc (Abbott Diagnostic Laboratories) are virtually identical to the original RIA test kit. In addition, all donor samples (128 specimens) administered to 57 cases of non-A, non-B hepatitis that were prospectively followed at Baylor College of Medicine for the Transfusion-Transmitted Viruses (TTV) Study group were retested with the EIA-recombinant anti-HBc assay. All 21 samples which were reactive in the original RIA anti-HBc test also were positive by the current EIA procedure. One sample was EIA positive/RIA negative, and 106 other samples were negative by both assays. Thus, commercial anti-HBc kits based on HBcAg derived by recombinant DNA technology, should retain their predictive value for reducing the incidence of non-A, non-B hepatitis as described in the prospective studies.     

Detection and characterization of hepatitis B virus of anti-hepatitis B core antigen-reactive blood donors in Quebec with an in-house nucleic acid testing assay

BACKGROUND: Hepatitis B virus (HBV) infection can be detected in blood donations by many serologic markers. Since the introduction of routine anti-hepatitis B core antigen (HBc) donor screening at Héma-Québec in April 2003, a large number of donors have been deferred on the basis of reactive anti-HBc test results. The objective of this study was to evaluate the correlation between the anti-HBc–reactive donations and the detection of HBV DNA with an in-house nucleic acid testing (NAT) assay.
STUDY DESIGN AND METHODS: The in-house HBV NAT assay is a conventional polymerase chain reaction amplifying part of the viral S  gene. From October 2004 to November 2005, a total of 1169 anti-HBc–reactive donations were tested with this in-house assay. The results were correlated with hepatitis B surface antigen (HBsAg) and anti-HBs markers. HBV DNA–positive samples were further investigated by DNA sequencing.
RESULTS: All HBsAg-positive samples were detected by the NAT assay. Overall, 38 (3.25%) of anti-HBc–positive samples were found to be positive for the presence of HBV DNA. Of these 38, a total of 12 donations with a low level of HBV DNA were HBsAg-negative. The sequencing results clearly showed various genotypes and subtypes within a same genotype.
CONCLUSION: The 3.25 percent HBV DNA positivity rate among the anti-HBc–reactive donations and more particularly the low level of HBV DNA observed in occult donations underline the importance of the use of a sensitive assay to detect HBV DNA in conjunction with other markers. The HBV genetic diversity found in our donor population reflects the province demographics, particularly in the Montreal area where most of the positive donors were from.     

Increased risk of a positive test for antibody to hepatitis B core antigen (anti-HBC) in autologous blood donors

Controversy exists about the suitability of blood from autologous donors for homologous use. We compared the infectious disease test results of 426 autologous donors, designated by donor history as suitable for homologous use, to those of 86,138 volunteer donations collected over the same 5 month period. Although donor characteristics differed, the relative risk of a positive test for anti-HBc in the autologous group was 2.09. When 413 autologous donors were compared to 413 volunteer donors matched for age, sex, and zip code, the relative risk of a positive test for anti-HBc in the autologous group was 3.2. If anti-HBc is a marker for non-A, non-B hepatitis transmissibility, then our autologous group is not as safe as our volunteer donors. We recommend that autologous blood, even when designated by donor history and laboratory screening results as suitable for homologous transfusion, not be used for other than the intended autologous recipient.