Multicenter study of a new fully automated HBsAg screening assay with enhanced sensitivity for the detection of HBV mutants

In a multicenter study a new, fully automated Roche Diagnostics Elecsys HBsAg II screening assay with improved sensitivity to HBsAg mutant detection was compared to well-established HBsAg tests: AxSYM HBsAg V2 (Abbott), Architect HBsAg (Abbott), Advia Centaur HBsAg (Bayer) Enzygnost HBsAg 5.0 (Dade-Behring), and Vitros Eci HBsAg (Ortho). A total of 16 seroconversion panels, samples of 60 HBsAg native mutants, and 31 HBsAg recombinant mutants, dilution series of NIBSC and PEI standards, 156 HBV positive samples comprising genotypes A to G, 686 preselected HBsAg positive samples from different stages of infection, 3,593 samples from daily routine, and 6,360 unselected blood donations were tested to evaluate the analytical and clinical sensitivity, the detection of mutants, and the specificity of the new assay. Elecsys HBsAg II showed a statistically significant better sensitivity in seroconversion panels to the compared tests. Fifty-seven out of 60 native mutants and all recombinant mutants were found positive. Among 156 HBV samples with different genotypes and 696 preselected HBsAg positive samples Elecsys HBsAg II achieved a sensitivity of 100%. The lower detection limit for NIBSC standard was calculated to be 0.025 IU/ml and for the PEI standards ad and ay it was <0.001 and <0.005 U/ml, respectively. Within 2,724 daily routine specimens and 6.360 unselected blood donations Elecsys HBsAg II showed a specificity of 99.97 and 99.88%, respectively. In conclusion the new Elecsys HBsAg II shows a high sensitivity for the detection of all stages of HBV infection and HBsAg mutants paired together with a high specificity in blood donors, daily routine samples, and potentially interfering sera.     

Detection of antibodies to hepatitis B core antigen using the Abbott ARCHITECT anti-HBc assay: analysis of borderline reactive sera

Routine use of the automated chemiluminescent microparticle immunoassay Abbott ARCHITECT anti-HBc for diagnosis of hepatitis B is limited in case of borderline reactive sera with low signal close to the cut-off index. In order to determine the significance of anti-HBc detection when borderline reactivity occurs using the ARCHITECT anti-HBc assay, a comparative study was designed. 3540 serum samples collected over a 2-month period in the hospital of Nice were examined for markers of HBV infection (HBsAg, anti-HBs and anti-HBc). One hundred seven samples with sufficient volume and with borderline reactivity by the ARCHITECT assay were tested by two other anti-HBc assays, a microparticle enzyme immunoassay (MEIA, AxSYM Core, Abbott Laboratories, IL, USA) and an enzyme linked fluorescent assay (ELFA, VIDAS Anti-HBc Total II, bioMérieux, Lyon, France). Only 46 samples were confirmed by the AxSYM and the VIDAS assays. Additional serological information linked to patient history showed that the remaining samples (61) were false positives (11), had low titer of anti-HBc antibodies (13), or were inconclusive (37). This comparative study highlighted the existence of a grey zone around the cut-off index. Confirmative results through a different immunoassay are needed to confirm the diagnosis of HBV on borderline reactive sera using the ARCHITECT anti-HBc assay.     

Comparison of the technical and clinical performance of the Elecsys® HBsAg II assay with the Architect®, AxSym®, and Advia® Centaur HBsAg screening assays

South East Asia has some of the highest prevalence rates of hepatitis B virus (HBV) infection (≥8%) in the world, and the emergence of hepatitis B surface antigen (HBsAg) mutant strains is a growing problem. Assays with the highest levels of sensitivity, including mutant detection, should be used for routine HBsAg screening. In this large multicenter study, the clinical and technical performance of the fully automated Elecsys HBsAg II assay was compared with the Architect, AxSYM, and Advia Centaur HBsAg assays for HBsAg screening. Nine laboratories (three each from Thailand, Korea, and Singapore) compared the Elecsys HBsAg II assay with their routine HBsAg screening assay against a range of stored and routine clinical samples, including recombinant mutants. The Elecsys HBsAg II assay demonstrated equivalent sensitivity and specificity to the Architect HBsAg assay. However, the Elecsys HBsAg II assay recognized a native mutant sample (L94S, L97V, L98V, T123A) that the Architect HBsAg assay failed to detect. The AxSYM and Advia Centaur HBsAg assays appeared less sensitive for the detection of early HBV infection and also failed to detect some of the recombinant mutant strains. There was almost complete agreement between the Elecsys HBsAg II assay and comparator assays with respect to routine serum samples. The results of this study demonstrate that the Elecsys HBsAg II assay is a highly sensitive and specific screening assay for HBsAg and detects reliably the most important and clinically relevant HBV mutants and genotypes. It is suitable for routine HBsAg screening in Asia. J. Med. Virol. 82: 755–762, 2010. © 2010 Wiley‐Liss, Inc.     

Evaluation of two new automated assays for hepatitis B virus surface antigen (HBsAg) detection: IMMULITE HBsAg and IMMULITE 2000 HBsAg

In recent years the diagnostic industry has developed new automated immunoassays for the qualitative detection of hepatitis B virus (HBV) surface antigen (HBsAg) in serum and plasma samples that are performed on analyzers that permit a high-speed throughput, random access, and primary tube sampling. The aim of the present study was the evaluation of two new automated HBsAg screening assays, IMMULITE HBsAg and IMMULITE 2000 HBsAg, from Diagnostic Products Corporation. The new HBsAg assays were compared to well-established tests (Auszyme Monoclonal [overnight incubation, version B], IMx HBsAg, AxSYM HBsAg, and Prism HBsAg [all from Abbott] and Elecsys HBsAg [Roche Diagnostics]). In the evaluation were included seroconversion panels, sera from the acute and chronic phases of infection, dilution series of various HBsAg standards, HBV subtypes and S gene mutants. To challenge the specificity of the new assays, sera from HBsAg-negative blood donors, pregnant women, and dialysis and hospitalized patients and potentially cross-reactive samples were investigated. IMMULITE HBsAg and IMMULITE 2000 HBsAg, although not as sensitive as the Elecsys HBsAg assay, were equivalent to the AxSYM HBsAg assay and showed a higher sensitivity than the Auszyme Monoclonal B and IMx HBsAg systems for detection of acute infection in seroconversion panels. The specificities (100%) of both IMMULITE assays on unselected blood donors and potentially interfering samples were comparable to those of the alternative assays after repeated testing. In conclusion, the new IMMULITE HBsAg and IMMULITE 2000 HBsAg assays show a good sensitivity for HBsAg detection compared to other well-established tests. The specificity on repeatedly tested samples was equivalent to that of the alternative assays. The rapid turnaround time, primary tube sampling, and on-board dilution make it an interesting assay system for clinical laboratory diagnosis.     

Multicentre evaluation of the Elecsys<Superscript>®</Superscript> hepatitis B surface antigen II assay for detection of HBsAg in comparison with other commercially available assays

Screening for hepatitis B surface antigen (HBsAg) demands highly sensitive and specific immunoassays with the ability to detect clinically relevant surface gene mutants—the presence of which is an increasing concern and can compromise test results. The objective of the study was to compare the clinical and technical performance of the fully automated Elecsys HBsAg II assay with other widely used HBsAg immunoassays in China. This was a multicentre study in which eight Chinese laboratories compared the Elecsys HBsAg II assay with the Architect HBsAg assay, AxSYM HBsAg assay, or generic microtitre plate (MTP) enzyme-linked immunosorbent assays (manufactured in China) against preselected samples, including recombinant surface gene mutants, and routine clinical samples. Elecsys HBsAg II was the most sensitive assay for detecting positive results in seroconversion samples: up to 14, 11, and 22 days earlier than the Architect, AxSYM, and MTP HBsAg assays, respectively. It also detected all 211 preselected HBsAg-positive specimens and all 13 recombinant HBsAg mutants; the AxSYM and MTP HBsAg assays failed to detect 3 and 10 mutant samples, respectively. Sensitivity was 100% for Elecsys HBsAg II with routine samples, compared with 99.1, 98.9, and 95.2% for the Architect, AxSYM, and MTP HBsAg assays, respectively. In conclusion, it was demonstrated that the Elecsys HBsAg II assay is suitable for routine HBsAg screening in China.     

Improved Detection of Hepatitis B Virus Surface Antigen by a New Rapid Automated Assay

The performance of hepatitis B virus (HBV) surface antigen (HBsAg) screening assays is continuously improved in order to reduce the residual risk of transfusion-associated hepatitis B. In a multicenter study, a new automated rapid screening assay, Elecsys HBsAg (Roche Diagnostics), was compared to well-established tests (Auszyme Monoclonal [overnight incubation] version B and IMx HBsAg [Abbott]). Included in the evaluation were 23 seroconversion panels; sera from the acute and chronic phases of infection; dilution series of various HBsAg standards, HBV subtypes, and S gene mutants; and isolated anti-HBV core antigen-positive samples. To challenge the specificity of the new assay, sera from HBsAg-negative blood donors, pregnant women, and dialysis and hospitalized patients and potentially cross-reactive samples were investigated. Elecsys HBsAg showed a higher sensitivity for HBsAg subtypes ad, ay, adw2, adw4, ayw1, ayw2, ayw4, and adr detection in dilution series of different standards or sera than Auszyme Monoclonal version B and/or IMx HBsAg. Acute hepatitis B was detected in 11 to 16 of 23 seroconversion panels between 2 and 16 days earlier with Elecsys HBsAg than with the alternative assays. Elecsys HBsAg and Auszyme Monoclonal version B detected HBsAg surface mutants with equal sensitivity. The sensitivity and specificity of Elecsys HBsAg were 100%. Auszyme Monoclonal version B had a 99.9% specificity, and its sensitivity was 96.6%. IMx HBsAg showed a poorer sensitivity and specificity than the other assays. In conclusion, Elecsys HBsAg permits earlier detection of acute hepatitis B and different HBV subtypes than the alternative assays. By using highly sensitive HBsAg screening assays, low-level HBsAg carriers among isolated anti-HBV core antigen-positive individuals can be detected.     

Should HBV DNA NAT replace HBsAg and/or anti-HBc screening of blood donors?

Prevention of transfusion-transmitted hepatitis B virus (HBV) has historically relied on serological screening of blood donors using progressively more sensitive HBsAg assays; in some countries anti-HBc assays have also been employed to detect chronic carriers with low-level viremia who lack detectable HBsAg. Nucleic acid amplification testing (NAT) for HCV and HIV has been successfully introduced to screen donors in many developed countries over the past several years; for logistical and cost reasons HCV/HIV NAT screening has been applied to mini-pools (MP) of eight to 96 donor specimens, with only minimal impact of MP dilutions on clinical sensitivity for interdiction of window period (WP) donations. In several countries (e.g., Japan and Germany), HBV NAT has been added to HIV/HCV MP-NAT blood donor screening with small incremental yields of HBsAg/anti-HBc-negative donations, and the major vendors of NAT systems (Roche and Chiron/Gen-Probe) have been developing triplex assays that include HBV DNA detection capacity without compromising HIV or HCV detection. Pooled specimen HBV NAT has also become the standard of practice for screening source plasma donors, with pressure to include HBV DNA detection as a required procedure for use of recovered plasma in manufacture of fractionated derivatives. However, there is controversy over the magnitude of the incremental yield and clinical benefit of HBV MP-NAT over serological screening strategies, as well as the impact of implementation of HBV NAT on need for retention of HBsAg and anti-HBc screening. This presentation will review recent modeled and empirical data on the value of HBV MP- and individual donation (ID)-NAT for detection of (1) pre-HBsAg WP units and (2) chronic anti-HBc-reactive carriers with undetectable HBsAg. The presentation will also review policy considerations and data that address the potential for discontinuation of either HBsAg or anti-HBc following implementation of HBV NAT. Finally it will address the cost effectiveness of incorporation of HBV DNA detection into HBV screening and NAT testing algorithms.     

Seven human immunodeficiency virus (HIV) antigen-antibody combination assays: evaluation of HIV seroconversion sensitivity and subtype detection

In this study, we evaluated the performance of two prototype human immunodeficiency virus (HIV) antigen-antibody (Ag-Ab) combination assays, one from Abbott Laboratories (AxSYM HIV Ag-Ab) and the other from bioMerieux (VIDAS HIV Duo Ultra), versus five combination assays commercially available in Europe. The assays were Enzygnost HIV Integral, Genscreen Plus HIV Ag-Ab, Murex HIV Ag-Ab Combination, VIDAS HIV Duo, and Vironostika HIV Uniform II Ag-Ab. All assays were evaluated for the ability to detect p24 antigen from HIV-1 groups M and O, antibody-positive plasma samples from HIV-1 groups M and O, HIV-2, and 19 HIV seroconversion panels. Results indicate that although all combination assays can detect antibodies to HIV-1, group M, subtypes A to G, circulating recombinant form (CRF) A/E, and HIV-1 group O, their sensitivity varied considerably when tested using diluted HIV-1 group O and HIV-2 antibody-positive samples. Among combination assays, the AxSYM, Murex, and VIDAS HIV Duo Ultra assays exhibited the best antigen sensitivity (at approximately 25 pg of HIV Ag/ml) for detection of HIV-1 group M, subtypes A to G and CRF A/E, and HIV-1 group O isolates. However, the VIDAS HIV Duo Ultra assay had a lower sensitivity for HIV-1 group M and subtype C, and was unable to detect subtype C antigen even at 125 pg of HIV Ag/ml. The HIV antigen sensitivity of the VIDAS HIV Duo and Genscreen Plus combination assays was approximately 125 pg of HIV Ag/ml for detection of all HIV-1 group M isolates except HIV-1 group O while the sensitivity of Vironostika HIV Uniform II Ag-Ab and Enzygnost HIV Integral Ag-Ab assays for all the group M subtypes was >125 pg of HIV Ag/ml. Among the combination assays, the AxSYM assay had the best performance for detection of early seroconversion samples, followed by the Murex and VIDAS HIV Duo Ultra assays.     

What is the role of serology for the study of chronic hepatitis B virus infection in the age of molecular biology?

To assess quantitative serology in chronic hepatitis B virus (HBV) infection, testing by novel immunoassays has been carried out on 202 specimens from untreated patients and in 83 samples from 10 patients with chronic hepatitis B treated with lamivudine. Serum samples were assayed for quantitative HBsAg, in comparison with quantitative HBV-DNA, and for anti-HBc IgM and the avidity index (AI) of total anti-HBc antibodies. The AI was high (mean: 0.93 +/- 0.19) in all groups, confirming the consistency of this procedure in chronic HBV infections. A low-level positivity (2-28 Paul-Ehrlich units/ml) for IgM anti-HBc was detectable both in HBeAg-positive and in HBeAg-negative untreated chronic hepatitis cases (mean S/CO values by the Abbott Architect assay: 0.51 +/- 0.12 and 0.48 +/- 0.10, respectively; correlation between assays: r = 0.685), while treated patients (mean: 0.20 +/- 0.15) and inactive carriers (mean: 0.17 +/- 0.21), were generally negative for IgM. The levels of HBsAg (IU/ml) showed a weak correlation with HBV-DNA (IU/ml). A difference in HBsAg levels was found between inactive carriers (1,935 +/- 2,887 IU/ml) and chronic hepatitis B cases, either treated (5,199 +/- 9,259 IU/ml) or untreated (14,596 +/- 15,227 IU/ml). Pre-treatment levels of HBsAg in patients undergoing lamivudine treatment were correlated with a sustained response to therapy over 13-33 months (mean: 27.3) of follow-up: mean HBsAg values were 1,576 + 1,487 IU/ml in five responders and 6,063 + 5,142 in five nonresponders or breakthrough responders (P < 0.05). The availability of standardized quantitative immunoassays for HBsAg and anti-HBc IgM may be considered in addition to quantitative HBV-DNA in the staging and monitoring of chronic HBV infection.     

Occult hepatitis B virus infection.

The detection of HBV DNA without HBsAg with or without the presence of HBV antibodies outside the acute phase window period defines occult HBV infection. This condition has been described in hepatocellular carcinoma (HCC), chronic hepatitis B, healthy HBV carriage and recovered infection, chronic hepatitis C and individuals without serological markers of HBV. The frequency of the diagnosis depends on the relative sensitivity of both HBsAg and HBV DNA assays. It also depends on the prevalence of HBV infection in the population. Occult HBV in blood donors has a wide range of potential origins within the natural history of the infection. It may originate from recovered infections with anti-HBs and persistent, low-level, viral replication, escape mutants undetected by the HBsAg assays or healthy chronic carriage. The last situation is mostly found with anti-HBc only. Over time, antibody markers may become undetectable leaving HBV DNA as the only marker of the infection. In all cases, the viral load is low, mostly below 10(4) IU/ml, often below 100 IU/ml. At these levels, nucleic acid testing (NAT) in pools is likely to be largely ineffective. Is occult HBV transmissible by transfusion? Carriers of anti-HBs or anti-HBc only were shown infectious in immunosuppressed organ or bone marrow transplant recipients. In immunocompetent recipients, there is no evidence that anti-HBs-containing components are infectious, even in low titre. Donations carrying anti-HBc only and HBV DNA can be infectious and this is a threat where anti-HBc is not screened. Anti-HBc screening identifies most occult HBV infection but not all. HBV NAT needs either extreme sensitivity or to be performed on individual donations to eliminate HBV DNA-containing units.     

Can the serological status of “anti‐HBc alone” be considered a sentinel marker for detection of “occult” HBV infection?

Some individuals have "occult" infection with hepatitis B virus (HBV), defined as presence of HBV genome in the serum or liver tissue without HBV surface antigen (HBsAg) in the serum. The aim of this study was to investigate whether serum antibodies against HBV core antigen in isolation ("anti-HBc alone") are a useful marker of "occult" HBV in patients with or without hepatitis C virus (HCV) infection. "Anti-HBc alone" was detected in the sera of 119/6,544 (1.8%) asymptomatic outpatients referred to the diagnostic laboratory for routine testing for viral hepatitis, 62/607 (10.2%) drug users, and 42/195 (21.5%) patients with hepatocellular carcinoma. Using three in-house nested-PCR amplification assays to detect HBV preS-S (S), precore-core (C), and Pol viral regions, respectively, "occult" HBV sequences were found in 9 of the 223 sera (4.0%) with "anti-HBc alone." The highest prevalence of "occult" HBV sequences (5.9%) was detected in "anti-HBV alone" sera of individuals referred to the diagnostic laboratory without HCV antibodies. Direct sequencing of all PCR products confirmed the specificity of the PCR reactions and revealed the predominance of HBV genotype D. The data presented in this study suggest that detection of "anti-HBc alone" could reflect unrecognized "occult" HBV infection and that physicians should consider investigating such patients with HBV molecular tests.     

Performance of the Elecsys Rubella IgG Assay in the Diagnostic Laboratory Setting for Assessment of Immune Status

Rubella in early pregnancy bears a high risk for congenital defects (e.g., cataracts, hearing loss, and heart disease) and for long-term sequelae in the newborn. Despite implementation of vaccination programs in many regions, the threat of devastating consequences from congenital rubella virus infection remains and careful screening of maternal immune status before and during pregnancy helps to reduce the risk. This study compared the performance of the Elecsys Rubella IgG assay with that of other assays routinely used for screening. Samples from 1,090 women undergoing routine antenatal care were tested using the Elecsys and Enzygnost Rubella IgG assays and the hemagglutination inhibition test. Samples with hemagglutination inhibition titers of <32 (n = 148) were additionally tested using the Vidas, AxSYM, Liaison, and Architect Rubella IgG assays. Agreement of qualitative results from the Elecsys, Enzygnost, and hemagglutination inhibition assays was good in all samples. All assays showed 100.0% specificity. In samples with hemagglutination inhibition titers of <32, the Elecsys, AxSYM, and Enzygnost assays showed higher sensitivity (>90.0%) than the other immunoassays (78.6 to 82.4%). The Elecsys assay reported significantly higher rubella virus IgG levels than the other immunoassays across the whole set of 1,090 samples, with the largest bias and deviation from limits of agreement in Bland-Altman analysis. In conclusion, the Elecsys assay is highly sensitive and specific with regard to qualitative results and suitable for routine automated screening. However, given the considerable variation between quantitative results from different immunoassays, testing methods should be documented and the same assay used throughout an individual''s antenatal follow-up wherever possible.     

Immunoglobulin isotypes of anti-HBc and anti-HBe and hepatitis B virus (HBV) DNA elimination in acute hepatitis B

Antibodies to hepatitis B core antigen (anti-HBc) and e antigen (anti-HBe) were assayed in 46 sera from ten patients with acute hepatitis B utilizing immunoglobulin class- and subclass-specific enzyme immunoassays (EIAs). The sera were sampled 1 to 512 days after onset of hepatic symptoms. Four patients cleared HBsAg rapidly, within 24 days, and six patients cleared HBsAg slowly, within 27-74 days after the onset of symptoms. In three of the patients with rapid clearance of HBsAg, hepatitis B virus (HBV) DNA was not detected in sera tested during the first week after onset. The fourth patient was not tested until 12 days after onset and was then found to be negative for HBV DNA. In four of the patients with slow clearance of HBsAg, HBV DNA was present during the first week of illness. In the other two patients, HBV DNA was not detected in the first serum, 11 and 17 days after the onset of illness. Anti-HBc IgM and IgA1 were detected in all patients, with maximum titers shortly after onset. Anti-HBc IgG1 was present in all sera tested. Anti-HBc IgG2 was not detected in any of the sera. Anti-HBc IgG3 and IgG4 were detected in all patient sera, with IgG3 paralleling IgG1, and IgG4 mainly in sera long after onset. Anti-HBe IgG1, IgG3, and IgG4 were detected in three, two, and two patients, respectively. Anti-HBe IgG2, IgM, IgA1, or IgA2 was not found in any patient. The time required for maximum titer of anti-HBc IgG1 was shorter in the patients with rapid clearance of HBsAg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Performance of HBsAg quantification assays for detection of Hepatitis B virus genotypes and diagnostic escape-variants in clinical samples

BackgroundThe impact of hepatitis B virus (HBV) genomic variability on the measurement of HBsAg level has been poorly evaluated.ObjectiveThis study was designed to compare the performance of all the available assays measuring HBsAg level in this setting.Study designA large selection of wild type HBV genotypes (n = 184) and HBsAg strains harboring mutations in the S gene (n = 81) from clinical samples was studied with three HBsAg quantification assays: Architect HBsAg (Abbott), LiaisonXL Murex HBsAg Quant (DiaSorin) and the Elecsys HBsAgII (Roche).ResultsThe overall percentage of positive results was 99.2% for Abbott, 98.9% for DiaSorin and 98.1% for Roche. Abbott and Roche assays provided an excellent concordance in HBsAg quantification (global mean bias of −0.006 logIU/mL). By contrast, DiaSorin underestimated HBsAg level with values 0.112 logIU/ml and 0.103 logIU/ml lower than Abbott and Roche, respectively. By contrast, DiaSorin slightly over quantified gtC (2.5% over the expected value) while Abbott provided values 6.2% lower than expected and 16.2% lower than what observed for the other genotypes. HBsAg quantitative assays were influenced by HBs protein substitutions irrespective to the genotype but no specific protein pattern that would particularly impair the quantification by one technique has been identified. However, Roche seemed to be particularly impacted by substitutions at 145 residue: 75% of under quantified samples carried a substituted 145 residue.ConclusionThis head-to-head comparison indicates a good correlation between all current systems used to quantify HBsAg but clearly shows an influence of both the genotype and the presence of “a” determinant variants in the absolute quantification of HBsAg. While these discrepancies may not translate into major clinical consequence, they may explain an absence of detection of weak concentration of HBsAg on some systems.     

Clinical performance evaluation of Elecsys HIV Duo,Anti-HCV II,HBsAg II,Anti-HBc II,and Syphilis assays for routine screening of first-time blood donor samples at a French blood donation center

ObjectivesImplementing fully automated analyzers has become a crucial safety step in blood donation centers. The Elecsys® assays were evaluated on the cobas e 801 module (Roche Diagnostics) for routine first-time blood donor screening.Materials & MethodsFive Elecsys infectious disease assays were tested on the cobas e 801 module at Etablissement Français du Sang, Montpellier, France (March–April 2018). The performance of Elecsys HIV Duo, Anti-HCV II, HBsAg II, Anti-HBc II, and Syphilis assays was compared with PRISM HIV O Plus, HCV, HBsAg, HBcore, and newbio pk TPHA assays (specificity analyses)/ARCHITECT Syphilis TP (sensitivity analyses), respectively. Specificity was determined in residual fresh serum samples from unselected first-time blood donors (n ≥ 5195 per parameter). Elecsys assay sensitivity was tested using 30 preselected, positively characterized samples per assay and compared with archived routine testing data for comparator assays.ResultsAcross all parameters, specificities for repeatedly reactive samples ranged from 99.81–100.00% for Elecsys assays and 99.71–99.98% for comparator assays. Sensitivities of Elecsys and comparator assays were the same for hepatitis C (85.19%), hepatitis B surface antigen (70.00%), hepatitis B core antigen antibodies (100.00%), and syphilis (100.00%). The sensitivity of the Elecsys HIV Duo assay was higher than the comparator assay (83.33% vs. 76.67%), but the difference was not statistically significant.ConclusionsElecsys infectious disease assays on the cobas e 801 module demonstrated high specificity and sensitivity for screening first-time blood donor samples, and were comparable with other commercially available assays. The Elecsys assays are reliable tests for screening blood donations.     

Coexistence of circulating HBsAg and anti-HBs antibodies in chronic hepatitis B carriers is not a simple analytical artifact and does not influence HBsAg quantification

BackgroundPresence at the same time of HBsAg and anti-HBs antibodies (HBsAg/Ab) is an entity sometimes encountered in chronic hepatitis B (CHB) carriers.ObjectivesThis study was designed to characterize such serological profiles and to assess the reliability of serological marker quantification by three commercially available assays in this setting.Study designAmong 2578 CHB identified patients, 129 (5%) had an HBsAg/Ab profile as determined by Abbott Architect. After exclusion of co-infections (HIV, HCV, HDV), HBV reactivation or HBIg treatment, 101 samples from 62 patients were tested for HBsAg and anti-HBs quantification using Architect, DiaSorin Liaison-XL and Roche Modular-Cobas. Influence of genotype and HBsAg variants was studied in 31 samples with HBV replication.ResultsHBsAg detection was confirmed with the 3 techniques for 98% (n = 99) of the samples while the HBsAg/Ab profile was concordant between all techniques for 65% of them. The overall correlation between the 3 HBsAg quantification techniques was good (R²: 0.94–0.97). The median HBsAg concentration was comparable for the 99 samples whatever the used technique but a bias of −0.11 and 0.02 log IU/mL were noticed for DiaSorin and Roche compared to Abbott, respectively. Anti-HBs quantifications were poorly correlated between techniques with major discrepancies observed. Genotype and substitutions within the “a” determinant showed an impact on HBsAg quantification.ConclusionsThe double HBsAg/Ab profile is not an analytical artifact and is confirmed on all commercially available techniques. While such profile does not influence HBsAg quantification, differences of HBsAg quantification were noticed according to HBV genotype or HBsAg variant.     

某艾滋病治疗示范区人免疫缺陷病毒感染者合并隐匿性乙型肝炎病毒感染的调查分析

目的 调查分析某艾滋病治疗示范区人免疫缺陷病毒（HIV）-1感染者中隐匿性乙型肝炎病毒（HBV）感染的情况及其影响因素.方法 采集某艾滋病治疗示范区97例经血感染HIV-1的感染者的血浆,采用酶联免疫吸附试验（ELISA）检测乙型肝炎表面抗原与抗体（HBsAg与抗HBs）、乙型肝炎e抗原与抗体（HBeAg与抗Hbe）、乙型肝炎核心抗体（抗HBc）及丙型肝炎抗体（抗HCV）;采用吸附柱法抽提HBV DNA;采用巢式聚合酶链反应（PCR）法检测HBV S区;采用流式细胞仪计数CD4＋T淋巴细胞.HBsAg阴性PCR阳性结果 者为合并隐匿性HBV感染者.合并隐匿性HBV感染者为实验组,未合并隐匿性HBV感染者为对照组.结果 97例HIV感染者中HBsAg阴性者92例（94.85%）.92例HBsAg阴性者中合并隐匿性HBV感染者27例（29.35%）,抗HCV阳性者73例（79.35%）.合并隐匿性HBV感染者和未合并HBV感染者CD4＋T淋巴细胞数、单独抗HBc阳性率分别为（212.11±133.1）和（318.9±172.2）cells/mm3、62.96%和18.46%,以上两指标两组比较差异均有统计学意义（P＜0.01）,两组间年龄、性别、是否合并HCV感染及抗HBs阳性率比较差异无统计学意义（P＞0.05）.结论 经有偿献血途径感染HIV者中存在隐匿性HBV感染;HIV阳性合并隐匿性HBV感染者中易出现单纯抗HBc阳性;CD4＋T淋巴细胞数低的HIV感染者更容易合并隐匿性HBV感染.     

Hepatitis B virus (HBV) infection and recombination between HBV genotypes D and E in asymptomatic blood donors from Khartoum, Sudan

Sudan is a highly endemic area for hepatitis B virus (HBV), and >5% of blood donors are chronically infected. To examine potential strategies to improve HBV blood safety, 404 replacement donor samples previously screened for HBV surface antigen (HBsAg) were tested for antibody to HBV core (anti-HBc), anti-surface antigen (anti-HBs), and HBV DNA. Of 145 anti-HBc-containing samples (36%) identified, 16 retested were HBsAg positive (11%). Anti-HBs was detected in 43/77 (56%) anti-HBc-reactive samples. Six samples were HBsAg(-)/anti-HBc(+)/anti-HBs(+) and contained HBV DNA, meeting the definition of occult HBV infection (OBI). OBIs had low HBV DNA loads (<10 IU/ml) and were genotype B (n = 1) or genotype D (n = 5). Pre-S/S and/or whole genome sequences were obtained from 47 randomly selected HBsAg-positive donors added to the previous 16. Genotype E was identified in 27 strains (57.5%), genotype D in 19 strains (40.5%), and genotype A2 in 1 strain (2%). Two outlier strains within genotype D ultimately were identified as recombinants of genotypes D and E with identical recombination points, suggesting circulating, infectious, recombinant strains. Anti-HBc screening does not appear to be a sustainable blood safety strategy because of the cost and the negative impact on the Sudanese blood supply, even when reduced by anti-HBs testing. Being at the junction between two main African HBV genotypes, genetic recombination occurred and became part of the molecular epidemiology of HBV in Sudan.     

Correlation between the Elecsys HBsAg II assay and the Architect assay for the quantification of hepatitis B surface antigen (HBsAg) in the serum

BackgroundHepatitis B surface antigen (HBsAg) clearance during chronic hepatitis B (CHB) infection is associated with improved long-term clinical outcome, so is considered an important therapeutic goal in CHB. Studies have shown that serum HBsAg quantification during, and at end of, treatment may predict long-term HBsAg loss.ObjectivesPerformance comparison of the qualitative Elecsys HBsAg II assay using a quantitative research protocol and an established quantitative HBsAg assay.Study designA dilution algorithm was developed for the Elecsys HBsAg II assay to allow quantification of HBsAg levels; this was used to measure HBsAg levels in a range of samples including sera from patients infected with different HBV genotypes, HBV mutants, and longitudinal samples from patients undergoing antiviral treatment. Results were compared with those from the quantitative Architect HBsAg assay.ResultsThere was significant overall correlation between Elecsys and Architect assays (correlation coefficient [r] = 0.97; p < 0.001). HBsAg levels measured with both assays correlated well in all phases of infection (r = 0.80–0.96), across all genotypes tested (HBV genotype A, r = 0.89; HBV genotype D, r = 0.97), and in samples with lamivudine-resistant mutations (r = 0.94). Bland–Altman analysis showed only minor discordance between assays in different phases of chronic HBV-infection (3.8–5.1%). This strong correlation was also present for sera with lower HBsAg concentrations. On-treatment HBsAg levels were similar when measured with either assay.ConclusionsUsing a simple dilution algorithm, the quantitative Elecsys HBsAg II assay reliably determined serum HBsAg levels in a wide range of samples, and showed very high correlation with the Architect HBsAg assay.     

Latent HBV infection in single blood donors

A total of 14,366 one-time blood donors were examined; 984 (6.8%) donors of them were found to have anti-HBc. All anti-HBc-positive samples were tested for HBsAg, IgM anti-HBc, HBeAg, anti-HBe, and specific DNA-HBV by polymerase chain reaction (sensitivity 400 coplml or higher). Anti-HBc in combinations with HBsAg, anti-HBe, IgM anti-HBc was detected in 29 (2.9%), 3 (0.3%), 5 (0.5%) donors, respectively. Specific HBV DNA was identified in 29 donors with HBs-antigenemia and in 9 anti-HBc positive donors in the absence of serum HBsAg. The activity of AIAt was correlated with neither HBsAg nor HBV DNA. Thus, latent HBV infection is 0.9% of anti-HBc-positive one-time blood donors and tests for anti-HBc may be useful in identifying persons who need a more meticulous study for HBV DNA.