Evaluation of performance of the RIBA processor system for automated analysis of the strip immunoblot assay for detection of antibodies to hepatitis C virus.

The performance of a new automated analyzer for the processing and interpretation of the RIBA Strip Immunoblot Assay (SIA), used in the diagnosis of hepatitis C virus (HCV) infection, was evaluated. Laboratory performance of the RIBA SIA was compared with that of two manually processed supplementary anti-HCV tests (RIBA HCV 3.0 SIA and INNO-LIA HCV Antibody III). Specificity of the automated processing of SIA was 100% for 90 selected anti-HCV-negative samples. On the other hand, 119 of 120 (99.2%) previously confirmed anti-HCV-positive samples were also positive when assayed on the automated processor. Results for all specimens except one (51 of 52) were concordant for manual and automated RIBA, while 15 of 68 sera tested with automated RIBA and the INNO-LIA assay showed different patterns of reactivity. Three HCV sensitivity panels and one seroconversion panel were also compared. The results show a high sensitivity for SIA NS3- and NS5-encoded antigens. Moreover, data obtained for the anti-HCV seroconversion panel and for samples with borderline or discordant anti-HCV enzyme-linked immunosorbent assay results suggest that bands with a relative intensity of >0.5 on the automated analyzer (theoretically negative) should be evaluated with care. Coefficients of variability ranged from 9 to 14.8% in an interassay reproducibility study. Overall, the performance of the automated analysis of SIA is comparable to that of the manual RIBA assay. The new automated processor for SIA bands proved to be sensitive and specific. Its use makes the optical scoring of bands unnecessary by indicating relative intensity values, which could be particularly useful in the follow-up care of anti-HCV-positive patients receiving antiviral therapy.     

Simultaneous detection of hepatitis C virus (HCV) core antigen and anti-HCV antibodies improves the early detection of HCV infection

To evaluate whether a new enzyme immunoassay developed for the simultaneous detection of hepatitis C virus (HCV) core antigen (Ag) and anti-HCV antibodies (anti-HCV Ab) (Monolisa HCV Ag/Ab ULTRA; Bio-Rad) could improve the early detection of HCV infection, we compared its sensitivity to that of anti-HCV, HCV core Ag, and HCV RNA assays. The populations studied included 12 blood donor samples positive for HCV RNA and HCV core Ag but negative for anti-HCV antibodies and 23 hemodialysis patients who developed anti-HCV Ab (seroconversion) during the follow-up. From these 23 individuals, 83 samples sequentially collected prior to seroconversion and 108 samples collected after seroconversion were tested. Six of 12 blood donations were positive by the HCV Ag/Ab assay. In the hemodialysis cohort, the 24 HCV RNA-negative samples were negative by the HCV Ag/Ab assay and 23 of the 59 HCV RNA-positive samples (39%) were positive. The HCV Ag/Ab assay detected HCV infection on average 21.6 days before the most sensitive antibody assay. The HCV Ag/Ab assay did not detect HCV infection as early as the HCV RNA assay (mean delay, 30.3 days) or HCV Ag assay (mean delays, 27.9, and 16.3 days by the HCV core Ag quantification assay and the HCV Ag blood screening assay, respectively). This new assay provides a notable improvement for the early detection of HCV infection during the so-called window period compared with anti-HCV Ab assays and could be a useful alternative to HCV RNA detection or HCV core Ag assays for diagnosis or blood screening when nucleic acid technologies or HCV core Ag detection are not implemented.     

Comparative evaluation of the Geenius HCV supplemental assay and Inno-LIA HCV score assay in detecting anti-HCV antibodies

ObjectiveThis study compared two assays aimed at confirming the presence of anti-HCV antibodies (Ab) after a positive screening: Geenius HCV supplemental assay (Bio-Rad, Marne la Coquette, France) and the Inno-LIA HCV score assay (Fujirebio, Les Ulis, France).Material and methodsA total of 180 archived samples were investigated including 119 samples collected at different stages of HCV infection in 25 hemodialyzed patients who underwent HCV seroconversion, 14 samples from 4 commercial seroconversion panels, 47 Ab positive/HCV-RNA positive blood donations of which 7 showing an single reactivity in confirmatory assays. Samples were investigated and results were interpreted with the two assays according to the manufacturers’ instructions.ResultsOverall, Geenius and Inno-LIA were concordant for 84% (151/180) samples: 38 negative, 17 indeterminate and 96 positive. Of the 29 discrepant results, 26 were overclassified with Inno-LIA. HCV seroconversion was detected with Inno-LIA 4 and 7 days prior to Geenius in two panels. The high positive rate observed with Inno-LIA (64%) compared to Geenius (54%) was mainly due to low reactivities considered positive according to interpretation criteria, which could affect specificity.ConclusionAlthough HCV supplemental assays are not recommended for the diagnostic of HCV infection, which is primarily based on HCV-RNA testing, both assays are suitable as second line anti-HCV tests when Ab screening is positive and RNA testing cannot be performed. Moreover, Geenius system provides an objective result in less than 30 minutes, which is compatible when a rapid diagnostic is required.     

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.     

Performance characteristics of the ARCHITECT anti-HCV assay.

INTRODUCTION: The ARCHITECT Anti-HCV assay is a fully automated high throughput chemiluminescent microparticle immunoassay (CMIA) for the detection of antibodies to structural and nonstructural proteins of the hepatitis C virus (HCV). To further enhance the performance of this test, the assay was modified to improve the specificity for blood donor specimens. METHODS: The specificity of the enhanced ARCHITECT Anti-HCV assay was evaluated by screening blood donor samples randomly collected from various German blood banks, as well as hospitalized patient samples derived from Germany and the US. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels and on a commercially available worldwide anti-HCV genotype performance panel. RESULTS: Apparent specificity of the modified ARCHITECT Anti-HCV assay in a blood donor population consisting of 3811 specimens was 99.92%, compared to 99.76% for the current on-market assay. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels. Seroconversion sensitivity equivalent to or better than the current on-market product was observed by testing 33 seroconversion panels. CONCLUSION: This study demonstrates that the modified version of the ARCHITECT Anti-HCV assay shows improved specificity for blood donor specimens compared to the current assay on market without compromising sensitivity. With the availability of the improved ARCHITECT Anti-HCV assay and the recent launch of the ARCHITECT HIV Ag/Ab Combo assay, the ARCHITECT system now offers a full hepatitis/retrovirus menu with excellent performance on a high throughput, random access, automated analyzer, ideally suited for blood screening and diagnostic applications.     

Multicenter evaluation of a new rapid automated human immunodeficiency virus antigen detection assay

Although human immunodeficiency virus (HIV) antigen assays are of limited value for monitoring antiretroviral therapy, they play an important role for confirmatory testing of fourth generation HIV screening enzyme immunoassay (EIA) reactive samples. In a multicenter study, a new automated rapid p24 antigen assay, Elecsys HIV Ag (Roche Diagnostics Boehringer Mannheim GmbH, Penzberg, Germany), was compared to FDA licensed tests (Abbott HIV-1 Ag monoclonal and Coulter HIV-1 p24 antigen assay). In the evaluation 27 seroconversion panels were included, sera from the acute phase of infection, single and follow-up samples from HIV antibody positive patients, dilution series of HIV antigen positive standards, sera and cell culture supernatants infected with different HIV-1 subtypes (A-H, and O) HIV-2 and recombinant HIV-1 (gag/env) isolates. To challenge the specificity of the new assay, 2565 unselected blood donors, sera from pregnant women, dialysis and hospitalized patients and 407 potentially cross-reactive samples were investigated. Acute HIV infection was detected in three to eight seroconversion panels earlier with Elecsys HIV Ag than with the alternative assays. Higher numbers of serum samples from HIV infected patients tested positive by Elecsys HIV Ag than with the comparative assays. All HIV-1 subtypes and HIV-2 isolates were recognized with Elecsys HIV Ag. Abbott HIV-1 Ag monoclonal and Coulter HIV-1 p24 antigen assay showed a variable sensitivity for the different HIV-1 subtypes. The specificity of Elecsys HIV Ag and Coulter HIV-1 p24 antigen assay were 99.8 and 99.93%, respectively. All the eight sera that were false reactive by Elecsys HIV Ag were tested negative with the Elecsys HIV Ag Neutralization Test. In conclusion, Elecsys HIV Ag was more sensitive than the alternative assays and showed a high specificity in combination with the neutralization assay. The very short incubation time of 18 min and the fully automated procedure of Elecsys HIV Ag which permits direct testing from the primary patient blood collection tube, represent a major improvement for routine laboratory diagnosis in comparison to the alternative assays.     

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.     

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.     

HCV免疫学诊断抗原与链亲和素融合蛋白的制备及应用研究

目的 制备带有链亲和素（SA）标签的丙型肝炎病毒（HCV）融合蛋白,并初步探讨其在抗-HCV ELISA检测中的应用.方法 构建了HCV诊断抗原与链亲和素融合蛋白重组表达质粒pET-11d-C44P-SA,在大肠埃希菌BL21（DE3）中表达,并用Western Blot进行鉴定,表达的融合蛋白经镍金属螯合（Ni-NTA）层析柱进行纯化,透析复性后分别包被生物素化以及普通酶联板,进行人血清抗-HCV检测.结果 成功构建了带有SA标签的重组表达质粒,其在大肠埃希菌BL21（DE3）中实现高效表达,制备的融合蛋白纯度可达90%以上.建立ELISA法进行人血清抗-HCV检测显示：融合蛋白包被生物素化酶联板检测灵敏度与特异性明显高于普通酶联板.结论 构建的融合蛋白作为包被抗原,结合利用SA标签与生物素化酶联板,明显提高了抗-HCV检出的灵敏度与特异性,该策略为进一步提高抗-HCV检测试剂的质量打下了基础.     

血清中丙型肝炎NS3抗原ELISA检测方法的建立和初步应用

目的 评价血清中丙型肝炎病毒(HCV)游离NS3抗原的酶联免疫吸附(ELISA)检测方法的特异性和灵敏度,初步探讨该方法在临床应用中的意义.方法 对77例正常人血清标本,173例抗-HCV阳性标本和3708例抗-HCV阴性的其他类型肝炎血清标本检测HCV游离NS3抗原;对部分HCV NS3抗原阳性标本进行验证,包括HCV RNA测定、中和试验和免疫斑点试验;对11例患者的25份系列血清标本进行了HCV游离NS3抗原、HCV RNA和HCV抗体的联合检测,并结合临床资料综合分析.结果 3708例抗-HCV阴性的其他类型肝炎血清标本中有48例为HCV NS3抗原阳性,其中3030例单纯乙型肝炎和445例其他类型肝炎血清标本中分别有44例和4例为HCV NS3抗原阳性;173例HCV抗体阳性标本中有42例为HCV NS3抗原阳性;77例正常人血清标本的HCV NS3抗原检测结果均为阴性;15例HCV NS3抗原阳性标本中有9例为HCV RNA阳性;23例HCV NS3抗原阳性标本的中和率和免疫斑点试验的阳性率分别为87.0%和69.6%;25份系列血清标本的检测结果显示其HCV NS3抗原的吸光度值与时间呈负相关,并有2例HCV NS3抗原阳性标本随着血清中HCV NS3抗原的吸光度值下降,其HCV抗体转阳.结论 血清中HCV游离NS3抗原的ELISA检测方法有较好的特异性和敏感度,在发展中国家应用此方法进行HCV感染的早期诊断有一定的临床意义和推广价值.     

Comparative evaluation of the VIDAS HIV DUO Ultra assay for combined detection of HIV-1 antigen and antibodies to HIV

The aim of the study was to evaluate the performance of the combined antigen and antibody HIV screening assay VIDAS HIV DUO Ultra (BioMérieux, Marcy l'Etoile, France) in comparison with two other combined tests: the former version of the same test (VIDAS HIV DUO, BioMérieux) and the AxSYM HIV Ag/Ab Combo assay (Abbott Laboratories, Rungis, France). A prospective study was performed on serum specimens received on a routine basis for HIV testing: 1443 blood samples were tested with the three assays. Sensitivity was 100% for the three tests. Specificity assessed on repeated false-positive samples was 99.86, 99.03 and 99.65% for VIDAS HIV DUO Ultra, VIDAS HIV DUO and AxSYM HIV Ag/Ab Combo, respectively. In addition, 14 seroconversion panels were tested with the VIDAS DUO Ultra and AxSYM HIV Ag/Ab Combo assays. For four of these panels, a positive signal was detected one blood sampling point earlier with the VIDAS DUO Ultra assay, corresponding to a higher sensitivity of the HIV antigen test. These results indicate that the VIDAS HIV DUO Ultra exhibits an improved specificity with comparison to the former version of this assay and an excellent sensitivity for early detection of HIV seroconversion.     

A chemiluminescent, magnetic particle-based immunoassay for the detection of hepatitis C virus core antigen in human serum or plasma

Hepatitis C virus (HCV) exposure in blood donors is determined serologically by the detection of anti-HCV antibodies in serum or plasma. However, a "window" period of 30-70 days after exposure exists where specific antibodies to HCV antigens are not detected. The use of nucleic acid testing for the detection of HCV RNA or antigen testing for the detection of HCV core protein have resulted in dramatic reductions in the pre-seroconversion window period. In this study, an automated HCV core antigen detection test was developed. This magnetic microparticle-based assay utilizes anti-HCV core monoclonal antibody to capture antigen present in human serum or plasma. Captured antigen is then detected using an anti-HCV core monoclonal antibody conjugated with a chemiluminescent compound. The specificity of this assay was established at 99% upon testing a population of normal volunteer blood donors. Sensitivity was determined by testing 16 commercially available HCV seroconversion panels representing genotypes 1a, 1b, 2b, and 3a. In each panel tested, HCV core antigen was detected prior to anti-HCV antibody, resulting in a reduction of the window period by greater than 23 days on average, and greater than 34 days on panels initially NAT negative. In addition, HCV core antigen was detected in >97% of HCV RNA positive/antibody negative specimens, exhibiting sensitivity nearly equivalent to nucleic acid testing in the pre-seroconversion window period for the panels examined.     

HIV-1, HCV and HBV seronegative window reduction by the new Roche cobas TaqScreen MPX test in seroconverting donors.

BACKGROUND: By shortening the pre-seroconversion window in the viral screening of donated blood, nucleic acid amplification testing greatly improves safety and efficiency, particularly when combined with multiple target detection and maximal automation. OBJECTIVES: Evaluation of seronegative window reduction during HIV-1, HCV and HBV infection by the novel cobas TaqScreen MPX test for simultaneous nucleic acid detection of HIV-1 (groups M and O), HIV-2, HCV and HBV using the cobas s 201 system. STUDY DESIGN: Testing of HIV-1, HCV, and HBV seroconversion panels (20 each) using the cobas TaqScreen MPX test versus reference immuno- and nucleic acid technology assays. RESULTS: The cobas TaqScreen MPX test detected HIV-1 and HCV infection earlier than immunoassays in 20/20 and 19/20 panels, and HBV DNA earlier than or on the same day as HBsAg in 19/20 and 18/20 panels, and later in 1 and 2 panels on neat samples and 1:6 dilutions. Pre-seroconversion sensitivity exceeded that of COBAS AmpliScreen testing in pools of 24. CONCLUSION: The cobas TaqScreen MPX test shortens the pre-seroconversion window in minipools of six, evidencing high sensitivity, and significantly enhances blood-screening efficiency by the simultaneous automated detection of multiple viruses in a single test.     

Multicenter clinical evaluation of the new 3rd generation assay for detection of antibodies against hepatitis C virus on the VIDAS® system

BackgroundDetection of antibodies (anti-HCV) against hepatitis C virus (HCV) is indispensable for screening and diagnosis of viral hepatitis and for the viral safety of blood, tissue or organ donations. It gains additional importance by the new HCV drugs which improve the therapeutic possibilities dramatically.ObjectiveTo evaluate the performance of a newly developed immune assay for anti-HCV based on the well-established VIDAS platform.Study designThe assay was evaluated with samples from anti-HCV negative blood donors and from patients with or without HCV markers in six centres in France, Spain and Egypt. The status of the samples was determined by using CE-marked immune assays (Architect, AxSym, Prism, Vitros), two immunoblots (RIBA, Inno-Lia) and/or HCV RNA results.ResultsSpecificity was 99.67% in 10,320 French blood donors without anti-HCV, 99.5% in 200 anti-HCV negative hospitalized European patients and 99.0% in 198 negative patients from Egypt. Sensitivity was 99.7% in 1054 patients pretested positive by other assays; 345 patients with known genotype had genotype 1–6; 61 patients were co-infected with HIV. VIDAS was reactive in 78% of 91 patients with uncertain or very weak anti-HCV. It became on average positive at day 37 with seroconversion panels.ConclusionsThis multicentric, international study with >12,000 samples show that the new VIDAS anti-HCV assay is very suitable for screening and confirmation of HCV infection. Sensitivity, specificity and recognition of seroconversion compare favorably with well-established CE-marked tests and help to clarify discrepant results obtained with other assays.     

Estimation of delay in detecting hepatitis C virus antibodies in pools compared to individual testing on seroconversion panels

Testing for anti-hepatitis C virus (HCV) antibodies in pools may reduce blood screening costs, making this approach affordable for developing countries, provided that the dilution of infected blood does not significantly increase the number of undetectable viral particles, especially in seroconverters. This study assessed the delay in detection of HCV antibodies in five HCV seroconversion panels, tested in pools of 6-48 samples, and estimated the risk of transfusion-transmitted HCV caused by pooling. The delay in detection of positive samples was 5-12 days for pools of all sizes, adding 7% to the risk of HCV transmission that occurs when blood donors' samples are tested individually.     

Performance evaluation of three automated human immunodeficiency virus antigen-antibody combination immunoassays

Three fourth-generation antigen/antibody combination assays (Elecsys, AxSYM, Architect HIV) and two third-generation (AxSYM, Centaur) HIV antibody immunoassays were evaluated. The evaluation panel of 479 samples included: nine tissue culture derived HIV-1 strains at four different p24 antigen concentrations (n=36), a p24 antigen sensitivity panel (n=10), 149 HIV-1 or HIV-2 confirmed antibody positive samples, ten anti-HIV-1 positive low titer samples, three seroconversion panels (n=21), and 253 HIV negative samples. The Architect had the best sensitivity for detection of HIV-1 antigen across eight HIV-1 subtypes, followed by the AxSYM while the Elecsys could not detect the highest antigen concentration evaluated (25 pg/mL) for eight of nine virus isolates. All assays showed 100% sensitivity for detection of HIV-1, group M, group O, and HIV-2 antibody positive samples. The Architect Ag/Ab Combo assay detected the first positive bleed of the three seroconversion panels and detected infection 4-26 days earlier than the third generation assays. Based on evaluation of 253 negative samples, assay specificity varied from 98.0% to 99.6%. The Architect HIV Ag/Ab Combo exhibited the best performance for specificity and detection of p24 antigen leading to closure of seroconversion window and demonstrating its utility for early diagnosis of HIV infection.     

Evaluation of two commercial enzyme immunoassays for diagnosis of hepatitis C in the conditions of a virology laboratory

BACKGROUND: Most studies which evaluate antibody detection assays are conducted on blood donors specimens, i.e healthy individuals. Sera collected in patients, vs healthy individuals, can make serological tests difficult because of possible non specific reactions interfering with serological tests. The aim of this work was to compare the specificity and the sensitivity of two commercial automated assays for the detection of hepatitis C virus antibody, Monolisa anti-HCV Plus on the Evolis automate (Biorad) and Axsym anti-HCV 3.0 (Abbott). PATIENTS AND METHOD: The prospective study of specificity included 2020 routine serum samples sent to our virology laboratory. The sensitivity was established with eight commercially available HCV seroconversion panels. RESULTS: The Monolisa and the Axsym assays showed a specificity of 99.64 and 99.12%, respectively. Of 49 specimens from eight commercially available HCV seroconversion panels, the number of positive results was 21 and 24 for the two tests, respectively. CONCLUSION: A statistical analysis of specificity and sensitivity results proved no significant difference between the two tests. Nevertheless, the Monolisa kits could be preferred for its more homogeneous sensitivity than the Axsym test and for its apparent better specificity. The final choice of a kit should also take into account the easiness to perform and an optimal integration in the usual practice of the concerned laboratory.