Impact of HCV 3.0 EIA relative to HCV 2.0 EIA on blood-donor screening

BACKGROUND: In 1996, the Ortho HCV Version 3.0 ELISA Test System (HCV 3.0 EIA) was licensed in the United States for donor screening but was neither mandated nor universally implemented. Data from two studies comparing the differential performance of HCV 3.0 EIA and HCV 2.0 EIA are presented. The first study evaluated the differential performance in a cross-section of screened whole-blood donors after implementation of HCV 3.0 EIA; the second study evaluated the differential performance of HCV 3.0 EIA in plasma donors acutely infected with HCV, identified during routine Abbott HCV 2.0 EIA and HCV NAT (using Roche Ampliscreen plate assay) donor screening. STUDY DESIGN AND METHODS: The first study evaluated HCV 3.0 EIA repeat-reactive donations from four US blood centers, identified during the first 5 months of HCV 3.0 EIA implementation. HCV EIA repeat-reactive donations confirmed by RIBA HCV 3.0 SIA were retested using both Ortho HCV Version 2.0 ELISA Test System and Abbott HCV 2.0 EIA. All EIA-discordant donations were tested by polymerase chain reaction (PCR). In the second study, Abbott HCV 2.0 EIA-nonreactive, HCV PCR-positive donors were enrolled in a follow-up study in which the index and follow-up samples were re-evaluated by HCV 3.0 EIA. RESULTS: In the first study, of 292,459 donations, 501 (0.17%) confirmed HCV 3.0 EIA-reactive donations were identified; 15 (0.005%) were nonreactive by Ortho HCV 2.0 EIA and were all HCV RNA negative. In the second study, Ortho HCV 3.0 EIA retesting of Abbott HCV 2.0 EIA-nonreactive, RNA-positive index donations identified 16 (23%) as 3.0 EIA reactive. In 42 panels with a discordant time of seroconversion, HCV 3.0 EIA sero-conversion preceded HCV 2.0 EIA in all cases (p < 0.001). Two donors with HCV 3.0 EIA-reactive index donations never seroconverted by HCV 2.0 EIA during 160 to 180 days of follow-up. CONCLUSION: These studies demonstrate that HCV 3.0 EIA compared to HCV 2.0 EIA can better detect 1) remote nonviremic HCV infections, 2) acute infection, and 3) HCV antibodies in cases of atypical seroconversion.     

Evaluation of automated nucleic acid extraction devices for application in HCV NAT

BACKGROUND: To further improve the safety of the blood supply, various national blood transfusion organizations presently use or are in the process of implementing routine HCV NAT in minipools. According to the Committee for Proprietary Medicinal Products (CPMP) of the European Union, the HCV NAT detection limit of the assay should be 100 IU per mL (270 geq/mL) for testing initial plasma pools. Paul Ehrlich Institute (PEI) regulations stipulate that 5000 IU per mL (13,500 geq/mL) must be detected to calculate the amount contributed by individual donations composing the minipool. The sensitivity for HCV RNA extraction achieved by three commercially available laboratory kits was compared. STUDY DESIGN AND METHODS: Nucleic acids from 1-in-3 serial dilutions of an HCV RNA run control (Pelispy, CLB) were extracted with three kits (Cobas Amplicor, Roche Diagnostic Systems; BioRobot 9604, Qiagen; and NucliSens Extractor, Organon Teknika). HCV PCR of all extracts was performed using a second-generation Cobas Amplicor HCV test and the Cobas Amplicor analyzer. RESULTS: The manual Cobas Amplicor, the BioRobot 9604, and the NucliSens Extractor setups allow a 95-percent HCV RNA detection limit of 129, 82, and 12 geq per mL, respectively. The maximal pool size for the manual Cobas Amplicor, the BioRobot 9604, and the NucliSens Extractor kits that would still meet the PEI criteria for HCV NAT in minipools was calculated at 104, 164, and 1125 donations, respectively. CONCLUSION: All three HCV NAT kits evaluated meet the criteria set by CPMP and PEI. The highest sensitivity for HCV NAT screening can be achieved with the high-volume NucliSens Extractor method in combination with the Cobas Amplicor HCV v2.0 test on the Cobas Amplicor analyzer.     

Outcome of an optional HCV screening program for blood transfusion recipients in Ireland

BACKGROUND: An optional (general) HCV testing program for blood and blood component recipients before the introduction of routine donor anti-HCV screening (October 1991) was launched in Ireland in 1995 to complement the targeted lookback program in progress at that time and to identify transfusion-transmitted hepatitis C. STUDY DESIGN AND METHODS: The public were informed of the opportunity to avail of screening by widespread media coverage. Screening was by an initial ELISA (Abbott 3.0, Abbott Laboratories) at the transfusion center laboratories. Reactive samples were referred to a virus reference laboratory where two additional ELISAs (Ortho 3.0, Ortho Clinical Diagnostics; and Murex 3.0, Murex) were performed. Confirmation of ELISA-positive samples was by a RIBA (RIBA 3.0, Chiron Corp.). All patients found to be anti-HCV- seropositive were tested for HCV RNA by PCR and were referred to a hepatologist. RESULTS: A total of 14,917 persons have been tested for hepatitis C in this program to date (85% women). Sixty-one people were confirmed positive for HCV by RIBA 3.0 (0.4%). Excluding persons with other risk factors (n = 15), the HCV positivity rate for blood component transfusion recipients (n = 46) was 0.3 percent. Of the 46 confirmed hepatitis C-positive blood component transfusion recipients, 32 were women (70%), 24 of whom received transfusion for obstetric or gynecologic indications (75%). Thirty-eight of 46 (83%) anti-HCV seropositive transfusion recipients tested had detectable HCV RNA by PCR. CONCLUSION: This program identified 46 transfusion recipients and 10 coagulation factor concentrate recipients, all of whom were previously unaware of their infection. The majority of HCV-positive transfusion recipients identified were women. This may reflect that women are longer living survivors of transfusion therapy or alternatively, in our experience, that Irish women perceive themselves at greater risk of hepatitis C because of the well-publicized association of this virus with recipients (women) of Irish RhIG.     

Comparative yield of HCV RNA testing in blood donors screened by 2.0 versus 3.0 antibody assays

BACKGROUND: Two HCV antibody tests (EIA 2.0 [EIA2], Abbott; and the Version 3.0 ELISA [EIA3], Ortho) are currently licensed for screening of US blood donors. Testing of donors for HCV RNA allows comparison of the sensitivities of the two antibody-screening assays. STUDY DESIGN AND METHODS: All allogeneic blood donations at 13 US test sites were screened for HCV RNA by testing plasma minipools using an investigational assay (COBAS AmpliScreen HCV test, v2.0, Roche Molecular Systems). Some sites screened for HCV antibody by EIA2 and some used EIA3. The frequency of RNA-positive and antibody-negative (RNA-pos and Ab-neg) donations among donors screened by each antibody assay was compared. Antibody appearance was assessed in a donor follow-up study. RESULTS: A total of 5.51 x 10(6) donations were screened for HCV RNA. Of these, 2.27 million were screened for antibody by EIA2, and 3.24 million by EIA3. Twenty-three donations were HCV RNA-pos and Ab-neg. The frequency of RNA-pos and Ab-neg donations was higher among donations screened by EIA2 (1 in 134,000), compared to those screened by EIA3 (1 in 540,000) (p = 0.001). Of the 17 RNA-pos and Ab-neg donations identified by test sites that used EIA2, 14 were retested by EIA3 and 10 (71%) were reactive. Most RNA-pos and Ab-neg donors appear to be in the process of seroconversion. Donors that were initially EIA2-negative and EIA3-reactive showed a more prolonged pattern of seroconversion compared to those that were initially nonreactive by both antibody assays. Four donors were EIA2-negative, EIA3-reactive, and RIBA-indeterminate (c33c) for at least 90 days, 1 for more than 317 days. CONCLUSION: EIA3 would have detected the majority of RNA-positive donations missed by EIA2. Some RNA-positive donors are EIA2-negative and EIA3-reactive for a prolonged period of time.     

Evaluation of a new automated third-generation anti-HCV enzyme immunoassay

The new Cobas Core Anti-HCV EIA was evaluated in two centers for its ability to detect antibodies directed to hepatitis C virus in human serum. This assay, which can be run fully automated on a random access analyzer, was compared with three other commercially available screening tests: the Ortho HCV 3.0 ELISA, the Murex anti-HCV, and the Abbott HCV EIA second generation. Positive or discrepant results were further investigated using the Wellcozyme HCV Western Blot or the Abbott Matrix HCV assays. The results obtained from analyzing 5045 serum samples showed a high correlation between the Cobas Core Anti-HCV EIA and the other screening assays, ranging from 98.9% to 99.9%. Diagnostic specificities and sensitivities ranged from 99.7% to 100% and from 98.8% to 100%, respectively. In this study, the Cobas Core Anti-HCV EIA proved to be a very convenient test, able to perform at the highest levels of sensitivity and specificity. © 1996 Wiley-Liss, Inc.     

Hepatitis C antibody intraassay correlation: is retest in duplicate necessary?

BACKGROUND: The hepatitis C virus antibody (anti-HCV) can be identified with third-generation immunoassays. The purpose of this study was to define the correlation or agreement between first and second reactive results of anti-HCV microparticle-based enzyme immunoassay (MEIA) and of chemiluminescence assays (ChLIAs) in blood donors, to determine whether repeat testing is necessary. STUDY DESIGN AND METHODS: Commercially available assays, third-generation HCV MEIA (Abbott), third-generation HCV ChLIA (Ortho), and third-generation HCV ChLIA (Abbott), were used to evaluate anti-HCV repeatedly reactive blood obtained from donations made at 23 Mexican blood centers over a period of 1 year. The intraassay correlation between first and second reactive anti-HCV tests with the Pearson r test and the coefficient of variation (CV) were determined. RESULTS: The intraassay correlation of 565 anti-HCV repeatedly reactive samples was 0.996 for the Abbott third-generation HCV MEIA, 0.995 for the Ortho third-generation HCV ChLIA, and 0.993 for the Abbott third-generation HCV ChLIA. The CVs of these assay systems were 2.82, 5.33, and 5.69 percent, respectively. CONCLUSION: A highly significant intraassay correlation between anti-HCV duplicates was found. Specimens with a single reactive anti-HCV result with the Abbott third-generation HCV MEIA, Ortho third-generation HCV ChLIA, and Abbott third-generation HCV ChLIA assays should be considered as positive and need not be retested. Such a change in the algorithm for blood donor screening is feasible because of the availability of highly automated platforms.     

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.     

Safety and efficacy of hepatitis C virus antibody screening of blood donors with two sequential screening assays

BACKGROUND: Reactive samples in hepatitis C virus (HCV) antibody screening of blood donors are currently referred for a confirmatory assay. This scheme is not optimally efficient and is expensive because of the lack of specificity and cost of confirmatory tests, as well as the need to discard false-positive donations. As in some human immunodeficiency virus antibody-confirmatory schemes, the safety and efficacy of confirming anti-HCV with two sequential screening assays were evaluated. STUDY DESIGN AND METHODS: Three combinations of two anti-HCV screening assays were used to test 75,874 blood donors. Results were compared with the routine testing scheme and HCV RNA detection in any enzyme immunoassay-repeatably reactive samples. RESULTS: The use of an alternative screening assay for repeat testing decreased the proportion of enzyme immunoassay-positive donors from 0.28 to 0.05 percent. All samples that were "confirmed" as positive by the standard combination of immunoassays and all HCV RNA-positive samples were detected by the sequential screening assays. No samples that had discordant results on primary and secondary screening assays were confirmed by recombinant immunoblot assay or were found to contain detectable HCV RNA. CONCLUSION: The combination of screening assays for anti-HCV confirmation was as safe as, cheaper than, and nearly as efficient as the standard testing scheme.     

Screening of blood donations by hepatitis C virus polymerase chain reaction (HCV-PCR) improves safety of blood products by window period reduction

Introduction of the nucleic acid amplification technique (NAT) as a screening test for blood donors to detect HCV RNA became mandatory on 1 April 1999. Few automated commercial systems are available for HCV RNA detection at the moment. The Cobas Amplicor HCV 2.0 System is able to perform fully automated amplification and detection of nucleic acids. A concentration of 98 IU HCV RNA/ml can be detected by the Cobas Amplicor HCV 2.0 System (n = 233, in 100% of the cases). With a pool size of 40 donor samples, the guidelines of the Paul-Ehrlich-Institute concerning sensitivity (5,000 IU HCV RNA per mL in a single donation) were followed. One whole blood donation was identified as HCV-RNA positive (anti-HCV IgG negative, GPT < 30 U/L) during a period of 5 months. No false positive test results could be observed. The internal control and the run control are primarily helpful to monitor methodological problems.     

Comparative evaluation of Abbott and Murex antibody assays and Roche Amplicor PCR for diagnosis of human hepatitis C

Of 135 serum samples from 135 patients suspected of hepatitis C virus (HCV) infection, 67 were detected by Abbott IMX antibody assay, 89 by Murex anti-HCV (version III), and 47 by Roche Amplicor polymerase chain reaction (PCR). Furthermore, 44 of the 62 positive serum samples by both Abbott and Murex antibody assays, 2 of the 27 positive samples by Murex antibody assay only, none of the 5 positive samples by Abbott antibody assay only, and one of the 43 negative samples by both Abbott and Murex antibody assays had measurable HCV RNA by Roche Amplicor PCR, suggesting active hepatitis C viremia. Whereas Abbott and Murex antibody assays were in agreement with each other in 103 of the 135 serum samples tested, they showed discrepancy with regard to the other 32. Despite generating a small percentage of false positives, Abbott and Murez antibody assays are useful in monitoring serum antibody levels of the past or continuing hepatitis C virus infection. Abbott IMX appears to be more specific than Murex anti-HCV (version III). The use of Roche Amplicor PCR provides a means of revealing active hepatitis C viremia, and helping clarify antibody indeterminate serum samples.     

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.     

我国5城市合格献血者血液HIV及HCV残余风险研究

目的研究我国献血者血液HIV及HCV残余风险;评估我国开展血液核酸检测(NAT)的可行性和必要性。方法采集乌鲁木齐、昆明、北京、广州、杭州5城市献血者血样,用Chiron Procleix HIV-1/HCV Assay血液核酸检测体系,对各项血清学筛查均合格的89 467份血液作16人份混合血样NAT检测,凡筛查不合格血样再作单人份检测;对于抗-HCV阴性而HCV RNA NAT阳性者,用备用管作抗-HCV、ALT、及HCV RNA NAT复检。结果共检出HCV RNA NAT阳性但抗-HCV EIA阴性标本3例,未检出HIV RNA NAT阳性但抗-HIV EIA阴性标本;在87 034份血清学筛查合格献血者中,检出HCV NAT阳性2例,其中1例复检ALT为254U/L,未检出HIVNAT阳性;在2 613份血清学筛查不合格者中,检出1例HCV NAT阳性但抗-HCV EIA阴性标本,该献血者抗-HIV阳性、ALT 372U/L;未检出HIV NAT阳性但抗-HIV EIA阴性的标本。结论血清学筛查使我国的血液安全性已有相当高的保障;而NAT技术可进一步提高血液的安全性,但在我国是否可应用于常规血液筛查,需考虑成本与效益比。此外,ALT筛查对排除抗-HCV漏检血液仍有一定的作用。     

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.     

Hepatitis C in blood transfusion recipients identified at the Oxford Blood Centre in the national HCV look-back programme

After the introduction in September 1991 of donor screening for hepatitis C, 95 potentially infectious blood donors who had given blood before this date were identified at the Oxford blood centre. Three hundred and ninety-nine blood components issued previously from these donors were identified in the course of the national HCV look-back programme. Of 399 questionnaires sent to hospital blood banks 392 were returned, identifying 290 recipients of whom 177 (61%) had died, and 113 (39%) were still alive 4–13 years after transfusion. One hundred and four recipients were traced and tested. Forty-nine recipients were not HCV infected. Forty-four of 58 (76%) recipients who received blood from donors found to be HCV RNA positive after September 1991 gave positive test results for HCV RNA. Eleven of 58 showed only antibody (anti-HCV), and 3/58 who had apparently received infectious blood showed no sign of past infection. The 11 who showed anti-HCV only, together with the three who showed no sign of past infection despite strong evidence of receiving HCV RNA-positive blood, had a mean age at transfusion of 27 years, compared with mean age at transfusion of 46 years in the 44 recipients with persistent HCV infection. Virus genotyping in 33/44 HCV RNA-positive recipients revealed five different genotypes. These did not seem to influence the outcome. Virus genotypes in 31 donor–recipient pairs showed complete concordance. Liver biopsies in 23/44 RNA-positive recipients showed minimal inflammation in four, mild in eight and moderate in 11. Liver fibrosis, Ishak grades 1–3, was present in 16/23 recipients. One other male recipient, not subjected to a liver biopsy, developed a hepatocellular carcinoma which caused his death at the age of 71, 8 years after transfusion.     

Testing of individual blood donations for HCV RNA reduces the residual risk of transfusion-transmitted HCV infection

BACKGROUND: To allow cost-effective RNA testing with NAT techniques, the national authorities of several countries have planned or already introduced tests of mixed specimens, that is, plasma pools. STUDY DESIGN AND METHODS: High-throughput extraction, amplification, and detection of HCV RNA from individual blood donations were optimized and validated. The feasibility of the method and the frequency of anti-HCV-negative, HCV RNA-positive donations were determined in a prospective study of 27,745 allogeneic and 792 autologous individual donations. RESULTS: The 50- and 95-percent detection limits of the method were determined at 44 IU per mL and 162 IU per mL, respectively (World Health Organization HCV reference material). When 201 HCV RNA-positive sera were taken as a reference, the sensitivity was 97.5 percent. The assay specificity was determined at 99.77 percent. During a 20-month period, two seronegative blood donors tested positive in HCV PCR. The viral load of these donations was 6 x 10(6) and 3 x 10(7) copies per mL, respectively. Thus, the yield of HCV RNA testing in this study was 7. 63 per 100,000 screened donations (95% CI, 1.25-22.07). In both PCR-positive donors, seroconversion was found in subsequent blood samples. CONCLUSION: This study compares the feasibility of single-donation HCV RNA screening, with the detection of a relatively high percentage of window-phase donations, to data reported from groups using HCV RNA testing of plasma pools. The relative yield of NAT of individual donations versus minipools should be directly investigated in the near future.     

献血者HCV RNA实时荧光定量PCR方法的建立

目的建立快速检测献血者中丙型肝炎病毒(hepatitis C virus,HCV)感染的方法。方法利用体外转录制备的HCV RNA转录体进行病毒RNA抽提方法及抽提效率的比较;将RNA转录体与正常血清进行不同数目的混合,对最佳混合标本数进行了摸索;建立HCV荧光定量PCR方法(fluorescence quantitative PCR,FQ-PCR),并对献血者进行混合标本HCV核酸检测。结果确定了比较理想的病毒RNA抽提方法;用于HCV核酸检测的混合标本数为24例;建立的荧光定量PCR方法能最低检测出10个copies/ml;采取24例混合血标本方法,FQ-PCR检测HCV RNA,576例ELISA检测HCV阴性的献血者未检测出HCV RNA。结论初步建立了献血者HCV感染的混合标本荧光定量PCR检测方法。     

Declining value of alanine aminotransferase in screening of blood donors to prevent posttransfusion hepatitis B and C virus infection. The Retrovirus Epidemiology Donor Study

BACKGROUND: Since the mid-1980s, blood banks in the United States have screened donors for elevated alanine aminotransferase (ALT) in an effort to prevent posttransfusion hepatitis. The present study was designed to quantitate the residual value of ALT screening following the implementation of hepatitis C virus (HCV) assays. STUDY DESIGN AND METHODS: Two approaches were used. First, a database of 2.3 million donations made by 586,507 volunteer blood donors between 1991 and 1993 was used to compare the incidence of seroconversion to hepatitis B virus (HBV) and HCV marker positivity in donors with elevated ALT values and with normal ALT values. Second, the duration of ALT elevation prior to HBV and HCV seroconversion was determined from 34 well-documented cases of posttransfusion HBV and HCV; elevated-ALT window periods were multiplied by rates of HBV and HCV incidence in donors to project the yield of ALT screening. Predictive value and cost- effectiveness analyses were also performed to compare the value of ALT screening before and after HCV screening was implemented. RESULTS: Both approaches indicate that ALT testing does not detect HBV in the window phase but does currently identify approximately 3 HCV window-phase donations per 1 million donations; this contrasts with ALT detection of approximately 1800 HCV-infectious units per 1 million donations prior to anti-HCV screening. Currently, only 8 in 10,000 donated units with elevated ALT (negative anti-HCV) are infected with HCV. The cost of continued ALT screening was estimated at $7,931,000 per quality- adjusted year of life saved. CONCLUSION: The yield, predictive value, and cost-effectiveness of ALT screening of blood donors have declined dramatically with the implementation of progressively improved anti-HCV assays. ALT screening of volunteer blood donors should be discontinued.     

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。     

无偿献血人群HCV感染的检测和输血残余风险分析

目的了解深圳地区无偿献血人群HCV感染状况,评估血液经EIA筛查抗-HCV后经血传播HCV感染的残余风险。方法采用两种EIA试剂对献血者血液进行抗-HCV筛查,采用核酸检测技术检测EIA检测＂合格＂标本中HCV RNA,对HCVRNA阳性标本进行荧光定量PCR检测病毒载量,并对PCR扩增产物进行测序和病毒基因亚型分析。结果共筛查1997～2009年期间的献血者254 570人份,发现抗-HCV阳性1401人份,阳性率为0.55%;对2002～2007年期间EIA检测＂合格＂的113639份献血者血液标本进行NAT检测,检测出1份HCV RNA阳性、抗-HCV阴性的血清转换窗口期感染的献血者血液,HCV残余风险高达1/113 639。结论 EIA筛查后血液安全性有了很好的保障,但由于HCV感染窗口期存在,经血传播HCV残余风险依然处于较高的水平,NAT应用对提高血液安全,降低输血传播HCV残余风险意义重大。