Transmission of HCV infection by RIBA indeterminate and positive blood units

A retrospective study was carried out on the recipients of 73 units of blood from 53 donors found reactive for anti-HCV. The donors were screened with anti-HCV enzyme-linked immunosorbent assay (ELISA C-100) and reactivity was confirmed with the first generation recombinant immunoblot assay (RIBA I). Fifty-two patients were recipients of blood from donors reacting as RIBA I 'indeterminate' and 21 of blood from RIBA I 'positive' donors. Only three recipients (5.8%) from 'indeterminate' donors were anti-HCV positive indicating that such donors are very seldom infectious. Eleven (52.4%) recipients from 'positive' donors had antibodies to HCV, indicating that not all RIBA-positive donors are necessarily infectious. Pretransfusion samples of the seropositive recipients were unavailable. All samples were analyzed with the first generation ELISA and with either the second-generation ELISA or RIBA (RIBA II) in order to evaluate test sensitivity. RIBA II was more sensitive than RIB I. One RIBA I indeterminate donor was positive by RIBA II. His recipient had antibodies to HCV. Twelve RIBA I indeterminate and three RIBA I positive donors were negative by RIBA II. All their recipients were anti-HCV negative. The second-generation ELISA was also shown to be more sensitive than ELISA C-100. The second-generation ELISA detected six confirmed anti-HCV positive recipients who were negative by ELISA C-100.     

Detection of free hepatitis C virus core antigen by enzyme-linked immunosorbent assay is not suitable for screening of granulocyte colony-stimulating factor-mobilized hematopoietic progenitor donors

BACKGROUND: Recent studies have shown that hepatitis C virus (HCV) can be detected in peripheral blood mononuclear cells of patients who are negative for the presence of anti-HCV and serum HCV RNA. The aim of the study was to evaluate the prevalence of HCV viremia in granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood progenitor cell (PBPC) donors by the use of a free HCV core antigen enzyme-linked immunosorbent assay (ELISA). STUDY DESIGN AND METHODS: A total of 28 samples from consecutive PBPC donors that were mobilized with G-CSF, and 13 samples from patients presenting with leukocytosis of greater than 20 x 10(9) per L from other causes, were tested by a free HCV core antigen ELISA. Positive samples were confirmed by use of neutralization assays. The specificity of the assay was studied in 48,911 healthy blood donors negative for the presence of anti-HCV. RESULTS: The free HCV core antigen assay showed a 46.4 percent positivity in PBPC donors mobilized with G-CSF and 61.5 percent in patients exhibiting leukocytosis in the absence of G-CSF treatment. All the samples were found to be false-positive samples, and those related with growth factor treatment did not react when G-CSF was discontinued. Overall specificity by the test in freshly collected blood donor specimens was 99.62 percent. CONCLUSION: Data indicate that the free HCV core antigen ELISA is not a valid test in diagnosing HCV infection in G-CSF-treated PBPC donors. Moreover, false-positive results of this test on blood donors might be indicative of elevated white blood cell numbers. The low specificity of this assay in the PBPC mobilization setting suggests that molecular assays should be the test of choice in the screening of G-CSF-treated donors.     

ORTHO抗-HCV酶联免疫试剂2种孵育试验程序在血液筛查中的比较研究

目的确定1种3代抗-HCV酶免试剂(ORTHO HCV 3.0 ELISA试剂)2种孵育试验过程在血液筛查中是否存在差异。方法随机留取常规献血者血液筛查中检出的抗-HCV反应性的血液标本180(人)份作HCVRNA检测,并用RIBA和不同于血站常规抗-HCV筛查的酶免试剂作抗-HCV复测;依据ORTHO HCV 3.0 ELISA检测试剂说明书中的长、短2种孵育检测程序,同时作对比检测。结果 180份初筛抗-HCV阳性标本中,有16份ORTHO HCV 3.0 ELISA 2种检测程序的检测结果不一致,其中5份为短孵育试验反应性、11份为长孵育试验反应性,短孵育试验漏检2份被确证抗-HCV阳性标本。ORTHO HCV 3.0 ELISA试剂的长孵育检测程序灵敏度高于短孵育试验程序,2种试验程序的S/CO值分布没有差别,但RIBA不确定标本其S/CO值分布在一定的灰区范围内。结论在献血人群血液筛查中,采用具有更高灵敏度的长孵育酶免程序和设定合理的结果判定灰区,有助于预防输血传播HCV,提高血液的安全。     

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.     

HCV抗体检测临界值附近样本传播HCV风险的研究

目的用尽可能低的消耗，达到HCV感染早期诊断，尽量缩短ELISA HCV抗体检测的“窗口期”，防止和减少经输血传播丙型肝炎的风险。方法采集初次检测抗-HCV（S／CO）样本测定值／临界值0．40～0．99的样本310份，采用“HCV抗体分片段酶联免疫确认试剂盒”进行补充旁证检测，对检测阳性及可疑阳性样本再进行HCV—PCR和RIBA及HCV—cAg检测。结果310份样本共检出单片段阳性样本25份，2个片段以上阳性样本3份，共计28份。HCV—PCR阳性3份，HCV—cAg阳性4份，RIBA检测3个条带阳性2份，1个条带阳性22份。28份样本中，抗-HCV分片段、PCR、HCV—cAg以及RIBA共同阳性1份，HCV—cAg与PCR共同阳性2份，HCV—cAg和RIBA共同1份。结论加强对抗-HCV检测阴性高值样本的重视，尽量缩短ELISA—HCV抗体检测“窗口期”。     

A new HCV core antigen assay based on disassociation of immune complexes: an alternative to molecular biology in the diagnosis of early HCV infection

BACKGROUND: An EIA based on immune complex disassociation of nucleocapsid proteins of HCV has been developed to detect and quantify HCV core antigen. STUDY DESIGN AND METHODS: To evaluate whether this new assay (trak-C, Ortho Clinical Diagnostics) could be an alternative to NAT during the window period, its sensitivity in this context was assessed, and its performance was compared with that of a first-generation HCV core antigen assay dedicated to the blood screening (HCV core antigen ELISA). Studied populations included nine HCV RNA-positive, HCV antibody-negative blood donors and 23 hemodialysis patients who underwent an HCV seroconversion. From these individuals, 81 samples (23 HCV RNA-negative and 58 HCV RNA-positive) sequentially collected during the phase before seroconversion were tested. RESULTS: The nine blood donor samples were positive for the presence of HCV core antigen by the trak-C, and 6 of 8 tested were positive for the presence of HCV core antigen by blood screening ELISA. In the hemodialysis cohort, the 23 HCV RNA-negative samples were negative with the two HCV core antigen assays. Among the 58 HCV RNA-positive samples, 46 of 57 (80.7%) tested were positive for the presence of HCV core antigen with the blood screening assay, and 57 of 58 (98.2%) were positive for the presence of HCV core antigen with the trak-C. The mean delays in detecting HCV infection between trak-C and the appearance of HCV antibodies, between HCV RNA testing and trak-C, and between trak-C and HCV core antigen ELISA were 58.2, 0.24, and 3.33 days, respectively. CONCLUSION: Trak-C was more sensitive than the blood screening assay and had similar performance to HCV RNA assay in the window period. Trak-C could constitute an alternative to NAT for the diagnosis of HCV infection during the window period, especially when molecular biology procedures cannot be implemented.     

Significance of the signal-to-cutoff ratios of anti-hepatitis C virus enzyme immunoassays in screening of Chinese blood donors

BACKGROUND: The correlation between signal-to-cutoff (S/CO) ratios of a second-generation hepatitis C virus (HCV) enzyme immunoassay (EIA; Abbott) and a third-generation HCV enzyme-linked immunosorbent assay (ELISA; Ortho) and confirmed HCV infection has been reported. The utility of the values for the Chinese anti-HCV EIA kits, however, has not been studied in evaluating test results in Chinese blood donors. STUDY DESIGN AND METHODS: A total of 156 donor samples repeat reactive for anti-HCV at routine screening from five representative regions of China were retested for anti-HCV by the Ortho third-generation HCV ELISA and six Chinese EIA kits and for HCV RNA by a human immunodeficiency virus-1 and HCV assay (Procleix, Chiron Corp.). The HCV RNA-nonreactive samples were further tested for anti-HCV by a third-generation recombinant immunoblot assay RIBA (Chiron Corp.). The positive result by either nucleic acid amplification test or RIBA was interpreted as confirmed HCV infection. RESULTS: The confirmed HCV prevalence rate in donors in five representative regions obtained in this study was 0.20 percent (77/37,900) in 2004. All seven anti-HCV EIA kits had a significant correlation between S/CO ratios and confirmed HCV infection. The threshold S/CO ratios, which predicted more than 95 percent of confirmed HCV infections for the Ortho, SABC, BGI-GBI, InTec, GWK, KHB, and WANTAI kits, were 3.8, 6.0, 7.0, 8.6, 10.0, 10.0, and 14.0, respectively. CONCLUSIONS: Anti-HCV EIA kits commonly used in Chinese donors screening demonstrate good correlation between S/CO ratios and the confirmed infection. For the Ortho third-generation HCV ELISA, the S/CO ratio of 3.8 determined by the US Centers for Disease Control and Prevention is applicable to Chinese blood donors. The Chinese domestic EIA kits evaluated show a diverse range of threshold S/CO ratios.     

Evaluation of the persistence and characteristics of indeterminate reactivity against hepatitis C virus in blood donors

BACKGROUND: A substantial number of individuals are excluded from blood donation due to indeterminate results in screening tests for hepatitis C virus antibody (anti-HCV). Disclosure of the characteristics of the indeterminate serologic pattern could optimize the testing and the management and care of blood donors.
STUDY DESIGN AND METHODS: Ninety-two former blood donors deferred from blood donation due to consistent reactivity in anti-HCV enzyme immunoassay and indeterminate HCV recombinant immunoblot assay (RIBA) results were retested for anti-HCV to examine the extent of disappearance of reactivity. In addition, they were screened for selected viral, immunologic, and inflammatory variables to detect possible causes of the test reactivity pattern.
RESULTS: After a median observation time of 75 months, 66 of 92 individuals had persistent indeterminate HCV RIBA results. Reactivity against the nonstructural NS5 antigen was the most frequent finding. A significant association was detected both between indeterminate reactivity in HCV RIBA and against the NS5 antigen independently and detectable antibody against adenovirus. Novel indeterminate reactivity showed increased prevalence during autumn and winter months.
CONCLUSION: Indeterminate HCV RIBA reactivity in blood donors persists over years. Increased prevalence during autumn and winter and association to detection of adenovirus antibody indicate that viral infection and cross-reactivity are etiologic factors in indeterminate HCV RIBA reactivity. Further prospective studies are needed to confirm the results.     

Hepatitis C core antigen in Polish blood donors

BACKGROUND: The goal of this study was to evaluate the feasibility of adopting the HCV core antigen ELISA (HCVcAg) for routine screening of Polish blood donors. STUDY DESIGN AND METHODS: A total of 133,279 donor samples were tested by ORTHO HCVcAg. All repeatedly reactive (RR) samples were tested by neutralization test for confirmation, RIBA HCV for anti-HCV, and by Cobas Amplicore for HCV RNA. All donations were tested for ALT level. RESULTS: The HCVcAg test specificity was 99.94 percent. In total, 1499 donations (1.12%) were initially reactive and 124 (0.09%) were RR. Antibodies to HCV were found in 22 out of 124 donors and HCV RNA was detected in 19 out of 22. In 10 out of the 19 HCV-RNA-positive donors, the HCVcAg neutralization test was positive. Among the 102 HCVcAg RR/anti-HCV-negative donors, there were 6 neutralization-test-positive individuals, and all were HCV RNA positive. Elevated ALT level was observed in one of them. During the follow-up studies of three HCVcAg RR/HCV-RNA-positive donors, seroconvertion was observed 5 to 7 weeks after the initial HCVcAg-positive result. In all, HCVcAg results became negative once antibodies to HCV were detected. CONCLUSION: The HCVcAg test proved to be feasible for routine screening in the Polish Blood Transfusion Service. Six HCVcAg RR/anti-HCV-negative donors were identified. The calculated residual risk in this study of donors in the preseroconversion window was 45 per million. Mandatory testing of every blood and plasma donation for HCVcAg or HCV RNA was recommended as of January 2, 2002.     

献血者抗-HCV不合格标本RIBA确认结果分析

目的分析献血人群ELISA试剂抗-HCV不合格标本确认结果,探讨抗-HCV ELISA试剂组合及灰区限的设置。方法收集113份ELISA试剂抗-HCV不合格标本,采用重组免疫印迹实验(RIBA)进行确认,并比较不同ELISA试剂的检测情况。结果 113份ELISA检测不合格标本中,RIBA确认阳性46份,不确定39份,阴性28份。确认阳性比例为40.7%。RIBA确认阳性的标本中,2种抗-HCV ELISA试剂检测结果均呈阳性反应的有44份;1种抗-HCV ELISA试剂呈阳性反应的标本中,RIBA确认阳性有2份,其余为阴性或不确定;灰区标本中,确认结果均为不确定或阴性。2种ELISA试剂检测均呈阳性反应的标本中,确认阳性率为78.57%。结论选用国产和进口试剂相组合,并设定灰区限,对保证血液安全意义重大。     

Low-positive anti-hepatitis C virus enzyme immunoassay results: an important predictor of low likelihood of hepatitis C infection

BACKGROUND: Tests for hepatitis C antibodies (anti-HCV enzyme immunoassays) are usually described as positive or negative. Several studies, mainly in blood donors, have found that specimens with low signal/cutoff (S/C) ratios are commonly negative when tested with a recombinant immunoblot assay (RIBA) or for HCV RNA. METHODS: We retrospectively reviewed 17 418 consecutive anti-HCV results from a screening program for high-risk veterans; 2986 (17.1%) samples were anti-HCV-positive, and 490 (16.4%) had S/C ratios 相似文献   

Routine HCV PCR screening of blood donations to identify early HCV infection in blood donors lacking antibodies to HCV

BACKGROUND: Detection of early hepatitis C infection of blood donors is still a major problem for blood transfusion. Common anti-HCV screening assays show differences in sensitivity and specificity. The often mild symptoms of acute hepatitis C also cause difficulties in the identification of early HCV infection. The feasibility and efficacy of routine screening of blood donations for HCV RNA were investigated. STUDY DESIGN AND METHODS: Blood donations (n = 251,737) were screened for HCV RNA over 4 years. RNA extraction, amplification, and detection were done by two commercial HCV PCR kits (HCV Cobas Amplicor and HCV Cobas Amplicor 2.0, Roche Diagnostics). Screening was done by pool testing with a maximum pool size of 40 serum samples. RESULTS: Three donations out of 251,737 were HCV RNA positive and anti-HCV negative. ALT levels of these donations were 271, 32, and 10 U per L. The HCV infection of a fourth HCV RNA-positive donor could not be identified by routine, second-generation HCV EIA (Abbott Diagnostika). In this case, two previous donations were also HCV RNA positive, and three second-generation test systems (Abbott) could not detect anti-HCV, whereas third-generation anti-HCV screening assays detected antibody with different sensitivity. The first HCV RNA-positive donation was identified only by the HCV ELISA 3.0 (Ortho Diagnostic Systems). The results of confirmatory assays like RIBA HCV 3.0 (Ortho) and Matrix (Abbott) indicate a restricted immune response to NS3 only. CONCLUSION: HCV RNA detection by PCR can be carried out routinely in blood donor screening without significant delay of release of the components. The residual risk of transmission can be reduced by identification of early infection, which can lead to an improved safety of blood components. RNA screening can also be advantageous in cases of incomplete or lack of antibody response to HCV.     

Combination HCV core antigen and antibody assay on a fully automated chemiluminescence analyzer

BACKGROUND: HCV exposure among blood donors is serologically determined by detection of antibodies to HCV (anti-HCV); however, the recent development of an assay for the detection of HCV core antigen identifies infection before anti-HCV development. Simultaneous detection of HCV core antigen and anti-HCV would shorten the window period before seroconversion over conventional HCV antibody screening assays. STUDY DESIGN AND METHODS: A prototype chemiluminescent immunoassay was developed for simultaneous detection of HCV core antigen and anti-HCV in human sera and plasma. The assay was performed on a single-channel instrument representing an automated serologic analyzer (PRISM, Abbott Laboratories) system. Sensitivity and specificity were evaluated by testing 23 HCV seroconversion panels and plasma or sera from volunteer blood donors. RESULTS: The prototype HCV core antigen and antibody combination assay detected 80 of 89 (89.9% ) HCV RNA-positive and antibody-negative specimens from 23 panels, thereby reducing the seroconversion window period by an average of 34.3 days compared to PRISM HCV antibody detection. All PRISM HCV antibody-positive specimens were detected by the combination assay for a relative sensitivity of 100 percent. The repeatedly reactive rate was 0.20 percent based on testing of 3017 screened anti-HCV-negative sera and plasma. CONCLUSIONS: The prototype combination assay was shown to detect HCV core antigen and anti-HCV simultaneously and significantly closed the time gap between the initial detection of HCV RNA and the first appearance of detectable antibodies to HCV.     

广州献血人群抗-HCV ELISA检测S/CO值与确证试验结果的相关性

目的研究广州献血人群抗-HCV ELISA检测试验S/CO值与确证试验(NAT和RIBA)结果的相关性。方法采用进口(Abbot或Ortho)和国产(科华)抗-HCV ELISA试剂对2009年2月～2012年4月广州血液中心采集的无偿献血者血浆标本作抗-HCV检测,从中随机收集664份双试剂呈反应性的血浆标本进一步作确证试验;使用ROC曲线分析3种ELISA试剂的S/CO值与确证试验结果的相关性。结果 ROC曲线分析显示3种ELISA试剂检测的S/CO值与确证试验结果具有相关性:以Youden指数最大时的S/CO值为最佳阈值,Abbot、Ortho及科华试剂分别为3.234、4.460和6.976,均可预测>95%的确证试验阳性结果。结论不同试剂具有各自的最佳S/CO阈值,可以通过S/CO值预测HCV感染确证试验的阳性结果。     

Antibody to hepatitis C virus in blood donors found positive for other agents. I. Treponemal infection

Summary. Stored serum samples from 169 blood donors found positive for TPHA were tested for antibodies to hepatitis C virus (anti-HCV) and to hepatitis B core (anti-HBc), as evidence of previous HBV infection, a condition known to be sexually transmissible. Only three donors were positive with a 'first generation' anti-HCV and all three failed to confirm with a recombinant immunoblot assay (RIBA). In contrast, 33 (19·5%) of the TPHA-positive donors were positive for anti-HBc. The results suggest that sexual transmission is not a major factor in the spread of HCV.     

Antibody to hepatitis C virus in blood donors found positive for other agents. II. Anti-HIV-1

Summary. Stored serum samples from 24 blood donors confirmed positive for anti-HIV-1 were tested for antibody to hepatitis C virus (HCV). Those repeatedly reactive using the anti-HCV ELISA screening test were retested by the HCV recombinant immunoblot (RIBA). Risk-factors for the contraction of HIV infection that had been elicited at formal counselling sessions were evaluated in relation to HCV/HIV modes of infection. The only two donors confirmed to be anti-HCV positive both admitted to intravenous drug use.     

Anti-hepatitis C virus serology in patients affected with congenital coagulation defects: a comparative study using three second generation ELISA tests

We determined the prevalence of anti-hepatitis C virus (HCV) antibodies in 34 patients affected with congenital coagulation disorders attending the Haemophilia Centre of Padua, Italy. Serological tests were carried out by three second generation enzyme linked immunosorbent assays (ELISA), two based on recombinant proteins (Ortho and Abbott) and one based on synthetic peptides (Behring) as antigenic substrate. The repeatedly reactive specimens were further assayed by the supplemental 4-antigen recombinant immunoblot assay (RIBA) (Chiron and Ortho). Moreover, we performed the dot-blot Matrix test (Abbott) on the samples showing discrepant results by the three ELISA tests. Twenty-six patients (76.5%) were anti-HCV positive using all three ELISA tests; 25 were confirmed by the supplemental RIBA test, the other one was indeterminate. Two samples were in a gray-zone only using the anti-HCV ELISA Abbott. These were positive by the RIBA; in contrast, such samples showed no reactivity with the Matrix test. In accordance with the current literature, these data show an equivalence between the 2nd generation screening tests (ELISA), at least when applied to a high risk population as in the present study. Further, these screening tests demonstrated a reliable specificity, since most of the ELISA-reactive specimens were confirmed by the supplemental RIBA test. In contrast, combined use of the anti-HCV tests could be useful when high sensitivity is requested, as in the case of blood donor pretransfusion screening.     

二种丙型肝炎病毒抗体确证试剂盒检测性能的比较

目的 应用丙型肝炎病毒抗体确证试验检测肝病患者血清抗HCV,进一步确认HCV感染.方法 对北京万泰生物药业股份有限公司初步研制重组免疫印迹法检测抗HCV试剂(简称CWT)与CHIRON RIBA HCV 3.0 Strip Immunoblot Assay进行比较,采用477份血清标本进行检测分析(慢性丙型肝炎病毒感染者血清350份、非甲非戊型肝炎患者血清7份、对照组采用乙型肝炎患者血清30份、戊肝肝炎患者血清30份及正常献血人员血清60份).结果 120份对照组非丙型肝炎患者血清均为抗HCV阴性;350份慢性丙型肝炎病毒感染者血清,国产试剂检出阳性341份,9份不确定;CHIRON RIBA HCV 3.0 SIA试剂检出阳性343份,不确定7份.7份非甲非戊型肝炎患者血清两种试剂检测均为阳性2份,阴性4份,不确定结果1份.两种试剂比较,检测结果一致率为99.16%(473/477),两者有很强的一致性(Kappa=0.98).结论 两种试剂对丙型肝炎病毒抗体的检测方法具有高度的一致性.特别是对于非甲-非戊型肝炎患者中的HCV感染者更有一定的诊断意义.

Abstract：

Objective To detect anti-HCV in serum of hepatic disease patients by performing the confirmatory test, and further to confirm HCV infection. Methods Two recombinant immunoblot assays (CWT and CHIRON RIBA HCV 3.0 Strip Immunoblot Assay) were used respectively to detect anti-HCV in 477 human serum samples, which comprised 350 HCV-infected patients' specimens, 7 none-A none-E hepatitis specimens, 30 HBV-infected patients' specimens, 30 hepatitis E virus infected patients'specimens, and 60 specimens drawn from blood donors. The latter three groups served as controls. Results A total of 120 control non-HCV-infected patients' specimens were negative when tested by both assays. Among 350 HCV-infected patients, 341 were positive and 9 were indeterminated by CWT assay; 343 were positive and 7 were indeterminated by CHIRON RIBA HCV 3. 0 SIA. Seven none-A none-E hepatitis specimens tested by both assays turned out to be 2 positive, 4 negative and 1 indeterminate. The consistency rate of these two assays was 99. 16% (Kappa=0.98). Conclusion CWT assay is highly coherent with CHIRON RIBA HCV 3.0 SIA assay in the methodology of anti-HCV antibody detection, which can be applied in the determination of HCV infection among none-A none-E hepatitis patients.