Hepatitis C virus seroconversion by a third generation ELISA screening test in blood donors.

The significance of seroconversion as detected by an ELISA screening test for hepatitis C virus (HCV) antibody with a negative supplemental/confirmatory recombinant immunoblot assay (RIBA) result was investigated. Of 118,220 established West Midlands blood donors with at least one negative HCV antibody screen, 43 had seroconverted in 1994 according to the ELISA but had negative RIBA-3 results. The paired archive serum samples of the pre- and postseroconversion donations of 29 seroconverting donors were tested by nested polymerase chain reaction (PCR) for the detection of HCV RNA. All 58 samples were negative by PCR. The absence of detectable viraemia in all tested seroconverting donors suggests that HCV infection was not responsible for seroconversion by ELISA.     

Hepatitis C virus antibodies and hepatitis C virus RNA in Chinese blood donors determined by ELISA, recombinant immunoblot assay and polymerase chain reaction.

Antibodies to hepatitis C virus (anti-HCV) were determined in Chinese blood donors from the city of Wuhan by a second generation ELISA screening test and a confirmatory recombinant immunoblot assay (RIBA II). Two materials of 281 and 222 sera were sampled under similar conditions in 1989 and 1990, respectively. The first collection of sera was sent to Sweden in lyophilized form, the second directly as fresh unfrozen sera. A high proportion (7.1%) of the lyophilized sera reacted positively in the anti-HCV screening assay, but only seven (2.5%) were positive by the RIBA confirmatory test. In four of these sera HCV-RNA could be detected by polymerase chain reaction (PCR) analysis. In the second material of fresh sera six reacted positively in the screening anti-HCV ELISA, but only one was RIBA positive and four were RIBA indeterminate. None of these sera was positive for HCV-RNA. Thus, the overall prevalence of anti-HCV among the 503 Chinese blood donors, as identified by RIBA, was 1.6%, and of HCV-RNA by PCR 0.8%. The confirmed antibody prevalence is higher than reported from the Western world. Caution about using data from the screening ELISA only, especially if sera have been handled in an unorthodox way, is emphasized.     

Coxsackie B virus infections in women with miscarriage

Serum samples from 1,765 consecutive Sardinian blood donors, negative for hepatitis B surface antigen (HBsAg) and for antibodies to human immunodeficiency virus (HIV) (anti-HIV), were evaluated for the presence of antibodies to hepatitis C virus (anti-HCV) by second-generation ELISA. Anti-HCV was detected in 25 (1.45%) of the 1,765 donors examined. Anti-HCV was found in 15 of the 1,690 (0.9%) donors with normal alanine aminotransferase (ALT) and in 10 of the 75 (13%) donors with elevated ALT (P < 0.0001). Of the 15 anti-HCV-positive donors with normal ALT, only five (33%) were confirmed to be positive by second-generation RIBA, six (40%) were indeterminate, while four (27%) were RIBA negative. HCV RNA, as detected by polymerase chain reaction (PCR) using a set of primers from the 5′-noncoding region, was found in six of the 15 (40%) donors with normal ALT, including five RIBA, positive and one indeterminant. Of the 10 anti-HCV-positive donors with elevated ALT, all were RIBA positive and eight (80%) had detectable HCV RNA. Thus, among ELISA-reactive donors, those with elevated ALT had a significantly higher probability of being positive for secondgeneration RIBA and HCV RNA compared to those with normal ALT levels (P = 0.028). None of the 65 donors with elevated ALT but negative for anti-HCV by ELISA had detectable serum HCV RNA, as compared to eight of 10 anti-HCV ELISApositive donors (P < 0.0001). However, although negative for HBsAg, 12 of the 65 (18%) had serum HBV DNA by PCR. This study demonstrates that the combined use of second-generation ELISA and RIBA anti-HCV assays is highly effective in identifying HCV infection, whereas the specificity of ELISA alone for the screening of blood donors with normal ALT values appears to be limited. In contrast, in donors with elevated ALT levels, there is a positive correlation between second-generation assays (ELISA and RIBA) and HCV viremia. The high proportion of inapparent HBV infection in blood donors with elevated ALT levels underlines the importance of this test for the prevention of transfusion-associated viral hepatitis.     

Determination of hepatitis C virus genotypes among blood donors in Ahvaz,Iran

This study aims to determine the genotypes of hepatitis C virus (HCV) among blood donors at Ahvaz Blood Transfusion Centre. Blood samples were taken from 2376 blood donors -$$$ 1795 (75.54%) male and 581(24.45%) female -$$$ who referred to Ahvaz Blood Transfusion Centre during 2007-2008. Detection of anti-HCV antibody for all the donors was carried out by ELISA and the confirmatory RIBA tests. HCV RT-PCR followed by RFLP test was carried out for anti-HCV positive samples. Out of 2376 blood donors, only 55 (2.3%) male donors showed to be positive for HCV antibody by ELISA and RIBA tests out of which 45(1.8%) donors were positive for RT-PCR test. Female donors were negative for HCV antibody. The result of HCV genotyping by RFLP test showed 24 (53.3%) for 1a, 17 (37.7%) for 3a (α) and 4 (8.8%) for 3a (β) genotypes respectively. In conclusion, high prevalence of 53.3% HCV 1a genotype was observed among blood donors in Ahvaz city.     

Interpretation of Ortho HCV Ab ELISA test results by chiron HCV recombinant immunoblot assay]

HCV infections are diagnosed by determining the circulating antibodies to the C 100 recombinant viral antigen using the ELISA method. Cut-off analysis from normal subjects and well documented NANBH patients suggests that screening of a low risk group such as blood donors might yield a relatively high ratio of false positives. An immunoblot assay (Chiron RIBA) using 3 recombinant antigens, C 100, 5-1-1 and SOD has been developed for evaluating the ELISA reactives as an additional, more specific assay. In the RIBA testing 51.5% were reactive and 28.5% were indeterminate in ELISA positive donor specimens, and 79.5% were reactive and 8.0% were indeterminate in ELISA positive non-A, non-B hepatitis patients specimens. These findings coincide with the ratio of theoretically calculated true positive. In a study done by Ortho U.S.A. viral RNA were detected in 70% of RIBA reactive, 33% of indeterminate and 3.6% non-reactive specimens by polymerase chain reaction (PCR). Furthermore, an advanced system using another immunogenic region of viral polyprotein including c33c encoded in NS3 has been on trial to evaluate the possibility of confirming HCV infection and detecting seroconversion at an earlier stage.     

Impact of screening donor blood for alanine aminotransferase and antibody to hepatitis B core antigen on the risk of hepatitis C virus transmission

The transfusion-related risk of transmission of hepatitis C virus (HCV) was evaluated in France for the periods before and after exclusion of donor blood units with the surrogate markers elevated alanine aminotransferase (ALT) levels and antibody to hepatitis B core antigen (anti-HBc). A total of 1,412 blood recipients undergoing surgery were followed up prospectively in the period from 1986 to 1989. The stored serum samples were tested for antibodies to HCV by an enzyme immunoassay (EIA) and the result in reactive sera confirmed by a recombinant immunoblot assay (RIBA). The risk of HCV transmission was estimated by the maximum likelihood method for a subpopulation of 892 recipients divided into three groups. Of 55 (3.9 %) EIA positive patients, 56.4 % were found to be positive prior to transfusion. HCV seroconversion (positive RIBA) occurred in 22 patients (1.6 %). The risk of HCV transmission per 1,000 transfused blood units decreased significantly from 4.11 in Group 1 (receiving non-screened blood) to 3.43 in Group II (receiving ALT screened blood) and to 1.40 in Group III (receiving ALT and anti-HBc screened blood). These results demonstrate that screening of donors for surrogate markers had reduced the risk of HCV transmission before the introduction of a systematic anti-HCV screening policy in France in March 1990.     

A comparison between one first generation and three second generation anti-HCV ELISAs: an investigation in high- and low-risk subjects in correlation with recombinant immunoblot assay and polymerase chain reaction

One first generation assay (manufactured by Ortho, test I) and 3 second generation anti-HCV ELISAs (manufactured by Ortho, Abbott, and UBI, tests II-IV) were compared. Sera from 4 different sources were used: (1) intravenous drug-users (IVDUs, n = 50), (2) blood donors (n = 1055), (3) all clinical samples from one day of routine anti-HCV testing (n = 89), (4) hemodialysis patients previously found negative by test I but clinically suspected to have a HCV infection (n = 11). Confirmatory anti-HCV tests were carried out with a second generation recombinant immunoblot assay (RIBA II). In sera positive exclusively by test IV, one antibody consumption test (UBI HCV Neutralization EIA) and one further immunoblot assay (INNO-LIA HCV Ab) were used. PCR for HCV RNA was carried out on all hemodialysis patient sera and in the RIBA II positive blood donor sera. The second generation ELISAs discriminated 11 more positive samples than the first generation test (2 IVDUs, 5 blood donors, 4 clinical samples). The 9 sera from blood donors and clinical samples were all RIBA II positive or indeterminate. The second generation tests thus showed increased sensitivity. The second generation tests also showed increased specificity in that 4 samples that were positive by test I but negative by the second generation tests, were also negative by RIBA II. With few exceptions, all RIBA II-positive and most of the indeterminate samples were positive by the second generation ELISAs. With few exceptions, all the RIBA II-negative samples were negative by the second generation ELISAs. Eleven blood donor sera were positive by test IV exclusively where RIBA II and other supplementary assays were negative. The recently introduced second generation anti-HCV ELISAs were found to have a higher sensitivity than the first generation test. The tests also showed a good concordance with the exception of test IV in the group of blood donor sera.     

Antibody to hepatitis C virus second envelope (HCV-E2) glycoprotein: A new marker of HCV infection closely associated with viremia

The second envelope protein (E2) of the hepatitis C virus (HCV) was cloned and expressed in Chinese hamster ovary (CHO) cells. This E2 glycoprotein was purified using ion exchange and lectin chromatography and used to construct an enzyme immunoassay for HCV E2 antibodies. The assay was shown to have good specificity, and detection of E2 antibodies was positively correlated (97.3%) to the presence of HCV RNA in serum and plasma. A high concordance between HCV 2.0 and E2 EIA reactivities was also observed. E2 antibody was the first serological marker to appear in 3/5 HCV seroconversion panels. This work demonstrated that 42.4% of core and 15.4% of NS3 indeterminate specimens also contained antibodies to E2, suggesting that HCV infection had occurred in these individuals. The E2 antibody assay was used to evaluate HCV 2.0 EIA-positive, HCV 3.0 EIA-negative plasma donors with indeterminate reactivity on RIBA HCV 2.0 or MATRIX HCV 1.0. Several HCV 3.0-negative specimens were shown to contain E2 antibodies in addition to an original indeterminate serological marker, primarily core. It is concluded that anti-E2 is a useful marker for determining HCV infection, and that the presence of antibodies to two nonoverlapping viral gene products suggests true HCV exposure. New HCV 3.0 blood screening tests should detect HCV 2.0-positive donors who present with an indeterminate pattern by RIBA or MATRIX and who also carry E2 antibodies. © 1995 Wiley-Liss, Inc.     

Low prevalence of antibody to hepatitis C virus in north east England

The prevalence of antibodies to hepatitis C virus (anti-HCV) was studied in North East England in blood donors, local multiply transfused patients, local high risk individuals, and chronic liver disease patients. Anti-HCV was detected by enzyme-linked immunosorbent assay (ELISA) in 2/1120 (0.18%) blood donors; 1/84 chronic renal failure patients on haemodialysis who had received 1,992 units of blood (seroconversion rate of 0.05% per unit transfused), 1/207 cardiac patients 6 months post cardiac surgery transfused with 1,403 units of blood (1 anti-HCV pre-operatively, seroconversion rate 0.07%), 40/50 haemophilia A patients treated with commercial factor VIII, and 38/100 intravenous drug users. In addition anti-HCV was detected by ELISA in 5/35 cryptogenic chronic liver disease patients, 5/5 confirmed by recombinant immunoblot assay (RIBA) (14%); 3/30 patients with autoimmune chronic active hepatitis, 2/3 by RIBA (7%); 2/50 primary biliary cirrhosis patients, 1/2 by RIBA (2%); 0/30 alcoholic cirrhosis patients; and 2/9 patients with hepatocellular carcinoma, 1/2 by RIBA (11%). HCV is uncommon in North East England; it may be implicated in the aetiology of a minority of cases of cryptogenic liver disease and less than 5% of autoimmune chronic active hepatitis and primary biliary cirrhosis.     

Hepatitis C virus infection in hemodialysis patients in southern Sweden: Epidemiological,clinical, and diagnostic aspects

A prevalence of hepatitis C virus (HCV) antibodies of 12% was found in 276 patients from 11 dialysis units. Between zero and 22% of the patients in the different units were anti-HCV positive. The epidemiology of HCV was studied in two units during a 2 year period by antibody assays and the polymerase chain reaction and correlated with clinical manifestations. Two types of epidemiologic patterns were found that may explain the wide difference of HCV prevalence described in different dialysis units. In one unit there was no evidence of spread within the unit, and the prevalence of HCV was dependent on the status of the patients entering for treatment. In the other unit, a clustering of infected patients could be seen in which 13 of 36 were infected during a 3 year period. Some patients who had not received blood transfusions were among the infected. Hepatitis C infection was the most common explanation for repeated abnormal transferase levels. Most of the HCV-infected patients reacted both for anti-HCV and HCV RNA. HCV RNA was in general detected earlier than anti-HCV seroconversion. Among 20 HCV RNApositive serum samples that were anti-HCV ELISA-positive 18 had indeterminate and two negative reactions by immunoblot (RIBA 2). Thus the RIBA 2 test should be used with caution as a confirmatory antibody test in this group of patients. © 1993 Wiley-Liss, Inc.     

Screening of blood donors for human cytomegalovirus (HCMV) IgG antibody with an enzyme immunoassay using recombinant antigens.

BACKGROUND: Screening of blood donors for human cytomegalovirus (HCMV) infection is usually performed by the combined detection of specific IgG and IgM antibody. However, in most of the cases of primary infection HCMV IgG seroconversion is observed concomitantly to IgM production and HCMV IgM antibody detection for blood donor screening is subject to a relatively high frequency of false positive results. OBJECTIVE: In the present study a newly established HCMV IgG ELISA based on recombinant antigens (anti-HCMV recombinant IgG ELISA, Biotest) was evaluated in terms of sensitivity and specificity for blood donor screening. STUDY DESIGN: A total of 442 serum samples including follow-up sera of five patients suffering from primary HCMV infection, selected seropositive and seronegative blood donors and routine specimens were comparatively investigated with three HCMV antibody ELISAs (anti-HCMV recombinant IgG ELISA, Biotest; Enzygnost anti-CMV/IgG + IgM, Dade Behring; and Captia CMV-TA, Centocor). RESULTS: IgG seroconversion was detected with anti-HCMV recombinant IgG ELISA as early as IgM in all five patients suffering from primary infection. The alternative ELISAs were less sensitive, detecting seroconversion one to three bleeds later in 2 (Enzygnost anti-CMV/IgG + IgM) and 4 patients (Captia CMV-TA), respectively. Anti-HCMV recombinant IgG ELISA showed a 99.1% agreement with Enzygnost anti-CMV/IgG + IgM and/or Western blot in the preselected blood donors and routine specimens. Relatively high numbers of false negative (n=20) and positive results (n=7) were obtained with Captia CMV-TA. CONCLUSIONS: Our preliminary data suggest that HCMV antibody screening of blood donors can be performed reliably by detection of specific IgG provided that a highly sensitive assay system is used.     

人类免疫缺陷病毒Ⅰ型和丙型肝炎病毒核酸联合检测试剂的评价

目的 了解人类免疫缺陷病毒Ⅰ型（HIV-1）和丙型肝炎病毒（HCV）核酸联合检测试剂检测的敏感性、特异性以及检测中国不同亚型样品的适应性。方法 用酶联免疫试剂对来自于不同地区的HIV感染者或可疑感染者献血员样品进行HIV抗体和HCV抗体检测。对HIV抗体阳性者进行抗体确证。用HIV-1和HCV核酸联合检测试剂对样品进行检测，对初次检测阳性者，用HIV RNA和HCV RNA鉴别试剂单独检测，区分是HIV RNA阳性或是HCV RNA阳性。结果 74份HIV和HCV抗体均阳性的样品，HIV／HCV RNA检测也为阳性，5份HIV和HCV抗体均阴性的样品，HIV／HCV RNA检测也为阴性；84份HIV抗体确证为阳性的样品，有82份检测为HIVRNA阳性，7份HIV抗体阴性的样品检测均为HIV RNA阴性，12份HIV抗体不确定的样品，有6份检测为HIV RNA阳性；81份HCV抗体阳性样品中有70份检测为HCV RNA阳性，22份HCV抗体阴性样品中有18份检测为HCV RNA阴性，4份检测为HCV RNA阳性。结论 该试剂的灵敏度较高，尤其在HCV抗体阴性样品中检出HCV RNA阳性者。因此，可用于献血员筛查，减少窗口期的传播。     

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.     

Prevalence of hepatitis C virus infections among heterosexuals with multiple partners

A study among heterosexual men and women with multiple sexual partners was carried out to assess the seroprevalence of antibody against hepatitis C virus (HCV). The 468 participants were recruited among visitors to the Clinic for Sexually Transmitted Diseases in Amsterdam. Sera were tested by an enzyme-linked immunosorbent assay (ELISA; Ortho), a recombinant-based immunoblot assay (RIBA; Chiron), and the polymerase chain reaction (PCR). A total of 468 persons were tested, and seven (1.5%) were found ELISA positive. Another 25 (5%) were ELISA indeterminate. Six of the seven ELISA-positive cases were RIBA positive. Further serum samples from five HCV ELISA-positive persons were tested by PCR, and four were found to be positive. The HCV ELISA-positive/RIBA-indeterminate reaction was PCR negative. None of the 17 RIBA-tested sera of the ELISA-indeterminate group yielded a positive result. There was a good correlation between an ELISA optical density/cut-off ratio greater than 2 and a positive RIBA result. The risk factor for HCV appeared to be the type of sexual partner, i.e., belonging to a "high-risk" group for human immunodeficiency virus infection and origin from hepatitis B-endemic countries. It is concluded that HCV may be transmitted through heterosexual contact but probably with low efficiency.     

High rate of false positives in blood donor screening for antibodies to hepatitis C virus

Summary Anti-hepatitis C virus antibody screening of blood donors in different countries revealed prevalences ranging from 0,4–1,4%. These results were obtained with an enzyme immunoassay based on a recombinant hepatitis C virus antigen. We applied a specific inhibition assay (neutralization assay) and a recombinant immunoblot assay to determine the specificity of positive reactions in the enzyme immunoassay.Of 2836 blood donor sera tested, 10 (0,35%) were reactive in the enzyme immunoassay, however, only 3 sera (0,1%) proved to be specifically anti-HCV positive in the inhibition assay. The recombinant immunoblot assay gave similar results. The prevalence of anti-hepatitis C virus antibodies among blood donors has been overestimated in recent publications. Furthermore the high rate of false positives in the enzyme immunoassay may explain reports claiming that only a minor part of EIA positive blood units transmitted the hepatitis C virus to recipients.The inhibition assay was also applied to sera of haemophiliacs and of patients with hepatopathy which had reacted positively in the anti-hepatitis C virus antibody enzyme immunoassay. The antihepatitis C virus specificity was confirmed for all sera from the haemophiliacs group (100%) and for 77% of the hepatopathy patients group. Thus, the anti-hepatitis C virus enzyme immunoassay has a high predictive value when it is used to screen groups with high risks of parenteral hepatitis C virus infection, however, its predictive value is very low when it is used for blood donor screening.Abbreviations EIA enzyme immunoassay - HCV hepatitis C virus - RIBA recombinant immunoblot assay - SOD superoxide dismutase     

Study on reliability of commercially available hepatitis C virus antibody tests.

The serodiagnosis of hepatitis C virus (HCV) infection was analyzed by a recombinant immunoblot assay (RIBA) with recombinant proteins encoded by the viral RNA isolated from our patients in Hamburg, Germany. The HCV RNA was amplified by PCR, and proteins encoded by the viral core and the NS3, NS4, and NS5 regions were expressed subsequently in Escherichia coli. The results obtained with our UKE RIBA were compared with the results of the Abbott HCV second-generation enzyme immunoassay (EIA). Serum samples from 270 patients, which were sent to us on the suspicion of HCV hepatitis and which were negative for hepatitis A virus and hepatitis B virus antibodies, were examined. In 227 cases (84.1%), there were identical positive (204 cases, 75.6%) or negative (23 cases, 8.5%) results in both tests. In 32 cases (11.9%), the reactive Abbott second-generation HCV EIA results could not be confirmed by the UKE RIBA and the HCV PCR. In follow-up studies conducted over 1 year, these results did not change. In three cases (1.1%), the UKE RIBA presented a positive result while the Abbott second-generation HCV EIA was negative. All three cases were positive in the HCV PCR and showed seroconversion in an HCV EIA 4 to 6 weeks later. In addition, 33 patient serum samples were examined by UKE RIBA in parallel with the Ortho RIBA 2.0. In three cases (9.1%), a positive Ortho RIBA 2.0 result could not be confirmed by the UKE RIBA and the HCV PCR. All three patients were free of complaints. The UKE RIBA showed also a smaller number of indeterminate results (3.0%) than the Ortho RIBA 2.0 (24.2%). This comparison study demonstrates that the commercially available HCV antibody tests should be further improved.     

丙型肝炎病毒E1抗体检测及临床应用

目的：研究丙型肝炎患者血清中HCV E1抗体，确定HCV E1抗原在抗体检测中的应用价值。方法：应用酶联免疫吸附测定（ELISA）方法检测80份卫生部第3代HCV血清参比品，821例职业献血员血清和720例临床肝炎患者血清中E1抗体。结果：用E1抗原单包板检查80份卫生部血清参比品的阳性符合率为70％、阴性符合率为100％；从821例职业献血员血清样品中检出E1抗体阳性率为1．9％；从720例临床肝炎患者血清中检出E1抗体阳性率为68％。大部分E1抗体阳性血清，同时也能和HCV的Core、NS3抗原及NS5A抗原呈阳性反应，但有个别血清只对E1抗原呈阳性反应。用市购HCV抗ELISA检测试剂盒检测为阴性的218例肝炎科门诊患者、813例献血员和848例一般人群血清，用E1抗原单包板复检，检出的阴性率分别为1．4％、1．1％和0．9％。在3例患者血清学转变的追踪研究中，HCV E1抗体都同现最早。结论：用E1工程蛋白检测E1抗体具有较高的灵敏度和特异性。E1抗体在HCV感染患者中普遍存在而且早出现，在临床诊断上是有意义的。     

Double-antigen sandwich ELISA for the detection of anti-hepatitis C virus antibodies

A double-antigen sandwich ELISA was developed a detection of HCV antibodies by a recombinant multi-epitope HCV antigen and a biotin-streptavidin amplification system. Three plasma specimens from 1708 individuals who were suspected previously to be HCV-positive using an HCV antibody diagnostic kit (Chuangxin, Xiamen, China) displayed negative results when using the ELISA. These results were validated by a recombinant immunoblotting assay (two were negative, and one was indeterminate). Among 889 blood specimens donated for clinical evaluation, 246 were positive and 630 were negative using the ELISA. The sensitivity and specificity of the ELISA were 98.7% and 100%, respectively. In 43 donors and 14 patients with chronic hepatitis C, the detectable rates for HCV IgM by both ELISA and the HCV anti-IgM detection reagents (Huimin, Shenyang, China) were 100%, and the detectable rate for HCV IgG using an indirect HCV-antibody detection kit (GWK, Beijing, China) was 98.3%. Thus, the double-antigen sandwich ELISA exhibits strong specificity and sensitivity and has been approved by the China State Food and Drug Administration (SFDA). The performance of the double-antigen sandwich ELISA was similar to the Ortho ELISA 3.0. It did not give false-negative results otherwise IgM was undetectable using an indirect HCV-antibody detection kit. This ELISA provides another method for the detection of HCV antibodies.