Routine Blood Donor Screening Research Articles

Health and economic impact of posttransfusion hepatitis B and cost-effectiveness analysis of expanded HBV testing protocols of blood donors: a study focused on the European Union.

Residual risk of posttransfusion hepatitis B (PT-HB) may be reduced through implementation of HBV NAT or the new, enhanced-sensitivity HBsAg assays in routine donor testing. However, there are some doubts about the cost-effectiveness of these new safety measures, because hepatitis B acquired in adulthood is not regarded as a severe disease in western countries. A computer model was designed to estimate the health outcomes and associated costs of patients with PT-HB. Results from this model and estimations of the residual risk of HBV transmission, the risk reduction yielded by the new assays, and their cost were used to calculate the cost-effectiveness of including the new HBsAg assays or single-sample HBV NAT in the routine screening of blood donors. The model predicts that 0.97 percent of patients with PT-HB die of liver disease (54% of them due to fulminant hepatitis). The mean loss of life expectancy was 0.178 years per patient, and the present value of the lifetime costs of treating PT-HB was 4160 euros per patient. Single-donor HBV NAT or the new HBsAg assays would increase the life expectancy of blood recipients by 16 (95% CI, 8-40) or 14 (95% CI, 7-28) years, respectively, per every 10 million donations tested. The projected cost per life-year gained was 0.79 (95% CI, 0.15-1.85) million euros for the enhanced-sensitivity HBsAg assays and 5.8 (95% CI, 1.9-13.1) million euros for single-donation HBV NAT, both compared with current HBsAg assays. If single-donation HBV NAT is compared with the new HBsAg assays, its cost- effectiveness ratio increases to 53 (95% CI, 16-127) million euros. PT-HB has few health or economic repercussions. Single-donation HBV NAT would provide a small health benefit at a very high cost. Instead, in some circumstances, the cost-effectiveness of enhanced-sensitivity HBsAg assays would be within acceptable ranges for new public health interventions.

Malaria Screening of Blood Donors in Saudi Arabia

Transfusion-associated malaria is a potentially serious complication that continues to pose risks in blood bank settings. There is a need for effective malaria screening of blood donations to improve on the current exclusion policies of potentially infected carriers on the basis of clinical and travel history. We evaluated the potential usefulness of ELISA screening for malaria antibody and P. falciparum antigen among Saudi blood donors. A total of 1756 donors were studied, 1100 from the malaria endemic Southern Region and 656 donors from the known malaria-free Riyadh area. The overall antibody prevalence for the antibody was 7.6%, in comparison to only 0.17% for the antigen. In the endemic region, the antibody positivity rate of 9.1% was almost double the rate in the non-endemic area (4.8%). There was no difference in the antigen prevalence rates; 0.18% in endemic and 0.15% in nonendemic areas. In malaria endemic countries like Saudi Arabia, excluding antibody-positive donations would result in too much wastage of blood units. However, antigen malaria testing appears to offer a potential utility, as only few donations would be rejected.

Clinical specificity and sensitivity of a blood screening assay for detection of HIV-1 and HCV RNA.

An HIV-1 and HCV NAT blood screening assay (Procleix HIV-1/HCV, Gen-Probe, Inc.) simultaneously detecting HIV-1 and HCV RNA) has been implemented. Donor plasma samples reactive in the Procleix HIV-1/HCV assay are tested with the HIV-1 and HCV discriminatory assays to resolve whether HIV-1 RNA, HCV RNA, or both are present. To determine the specificity of the Procleix HIV-1/HCV assay, data were analyzed for samples from 192,288 donations, tested in 16-member pools. To determine sensitivity, data were analyzed for 2014 commercial samples known to contain HIV-1, HCV, or both, as well as 10 HIV-1 and 10 HCV commercial seroconversion panels. The specificity of the Procleix HIV-1/HCV assay was 99.7 percent. The HIV-1 and HCV discriminatory assays showed similar specificity. The sensitivity of the Procleix HIV-1/HCV assay was 99.9, 99.6, and 100 percent, respectively, for samples containing HIV-1, HCV, or both. The Procleix discriminatory assays were comparably sensitive. The Procleix discriminatory assays detected all tested samples of known HIV-1 subtype or HCV genotype. Procleix HIV-1/HCV testing of seroconversion panels showed that the median times to a positive reaction for HIV-1 and HCV were reduced by 3 and 25 days, respectively, compared to serologic tests. These studies support the use of the Procleix HIV-1/HCV assay for routine blood donor screening.

HEPATITIS B AND C AND RENAL FAILURE

Hepatitis C is the most common cause of liver disease in the dialysis patient. The prevalence of chronic hepatitis C determined by anti-HCV testing in this population ranges from 6% to 38%. Using second generation EIA assays, the prevalence of anti-HCV among patients participating in the 1997 National Surveillance of Dialysis Associated Diseases in the United States was 9.3%. Polymerase chain reaction testing for HCV RNA has shown that the prevalence of HCV infection can be as high as 20% to 30% of dialysis patients. The causes and source of infection in patients with chronic renal failure on hemodialysis are multiple. Before the introduction of routine screening of blood donors for anti-HCV, blood transfusions were an important risk factor for acquisition of hepatitis C. Other potential sources of infection include exposure to contaminated equipment and nosocomial routes such as patient-to-patient exposure. The risk of infection appears to correlate with the duration of hemodialysis and the number of transfusions. Interestingly, dialysate and buffers have been shown to be virus free even when used in hepatitis C infected patients. The natural history of chronic hepatitis C infection in patients with renal failure is not well characterized. Although persistent elevations in ALT levels occur in 12% to 50% of dialysis patients, the frequency of persistently normal ALT levels in HCV-infected dialysis patients appears to be higher than in HCV-infected patients without renal failure. Overt liver disease and liver failure rarely occur. The degree of inflammation in liver biopsies of renal failure patients is usually mild. Thus, progressive liver disease may be less common in patients with advanced renal disease but further studies are required to assess the true impact of hepatitis C infection in this high risk population. The impact of hepatitis C infection on morbidity and mortality of patients with end-stage renal disease remains poorly defined. Initial studies have failed to show a significant increase in mortality among HCV-infected hemodialysis or renal transplant patients within the first 5 years following transplantation. In contrast, recent studies with extended follow-up of renal transplant recipients suggest that hepatitis C infection may affect patient and graft survival during the second decade. Further studies are required to identify the mechanisms of infection of patients with end-stage renal disease and to define better treatment strategies for these patients before and after kidney transplantation.

The risks of transfusion-transmitted infection: direct estimation and mathematical modelling

Direct measurement of the risk of transfusion-transmitted infection (TTI) is practical and accurate only if the level of risk is high. Historically, studies that established frozen repositories of transfusion recipient and/or blood donor samples were important in establishing the risk of many TTI agents, including the human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). However, given the current very low risk of TTI, mathematical modelling is necessary to estimate the magnitude of such a risk. For agents for which routine blood donor screening is performed, most of this risk comes from transfusion of units collected in the window period between donor infection and a positive blood screening assay. The incidence/window period model has been used to estimate the magnitude of such risks (of the order of 1:100000 to 1:1000000) and for predicting the extent of risk reduction that can be expected with implementation of new tests. Direct estimation and mathematical modelling approaches are both important tools for future assessment of potential, new or emerging TTI agents.

False-negative testing errors in routine viral marker screening of blood donors. For the Retrovirus Epidemiology Donor Study.

The contribution of testing errors to the risk of virus transmission by transfusion depends on the rate of false-negative testing errors and the prevalence of infected seropositive donations. Although the false-negative testing error rate has been estimated at 0.1 to 1 percent on the basis of proficiency studies, it has not previously been measured in routine donor screening. A 1991 to 1995 database containing 5,153,153 donations from 1.5 x 10(6) donors (including autologous donors) was searched to identify donors who tested seropositive for HIV, HCV, HTLV-I or II and who attempted subsequent donations. The false-negative rate in routinely screened follow-up donations was determined, and false-negative cases were investigated to identify the cause. Subsequent donations (n = 2015) by 1224 donors with confirmed-positive results were identified. Eleven (0.5%) of these donations did not react in EIA. Ten of the 11 false-negative cases were attributable to borderline-reactive donations. On subsequent donations, there were borderline-nonreactive results on HTLV-I (2 cases), first-generation HCV (5 cases), and second-generation HCV (3 cases) EIAs. The final case was strongly reactive for HCV in a second-generation EIA on two donations (signal-to-cutoff [S:C] ratio >3.5), followed by a baseline nonreactive result on a third donation (S:C = 0.05). False-negative testing results occur infrequently during routine infectious-disease donor screening. Although most false-negative results occurred with borderline-reactive HTLV-II samples and/or early-generation HCV EIAs, frank technical errors (e.g., sample mixup or failure to add sample to EIA well) also occur at a low rate (0.05%; 95% CI, 0-1.5%). Process enhancements designed to reduce errors (e.g., enhanced automation of data management and testing systems and process controls for EIAs) are warranted to detect and prevent false-negative results.

Hepatitis C virus infection and bone marrow transplantation: a cohort study with 10-year follow-up.

Before the introduction of routine blood donor screening in 1991, marrow transplant recipients were at significant transfusion-associated risk for infection with hepatitis C virus (HCV). We followed a cohort of 355 patients undergoing transplant in Seattle during 1987 to 1988 to determine (1) the impact of pretransplant HCV infection on the occurrence and severity of venocclusive disease (VOD); (2) the impact of HCV infection on liver dysfunction, other than VOD, occurring between 21 and 60 days after transplantation; and (3) the natural history of post-transplant HCV liver disease with a 10-year follow-up. HCV-RNA status was determined on serum stored before transplant and at day 100 post-transplant. Sixty-two (17%) patients were HCV-RNA positive before transplant, and 113 (32%) were HCV-RNA positive by day 100 post-transplant (or before death). Severe VOD developed in 22 of 46 (48%) evaluable patients with pretransplant HCV infection and in 150 of 229 (14%) evaluable patients without HCV (P <.0001). In multivariable analysis of risk factors for developing VOD, pretransplant HCV infection associated with elevated serum aspartate transaminase (AST) levels predicted the development of severe VOD (relative risk, 9.6; P =.0001). The presence of HCV with normal AST levels before transplant was not a risk factor for severe VOD. Between 21 and 60 days after transplant, HCV-RNA positive-patients had higher AST levels (median 101 U/L), but similar alkaline phosphatase and total bilirubin levels compared with HCV-negative patients, suggesting that cholestatic liver disease (particularly graft-versus-host disease [GVHD]) was not related to HCV infection. An acute flare of hepatitis (AST >10 times the upper limit of normal) developed at a mean of 136 +/- 58 days in 31% of HCV-positive patients; no patients developed fulminant hepatitis. Between 5 and 10 years after transplant, 57% of HCV-positive and 6% of HCV-negative patients had mild to moderate elevations of AST (P <. 0001), but HCV infection was not associated with excess mortality between 3 and 10 years after bone marrow transplantation. In summary, HCV infection with elevated AST levels is a significant risk factor for severe VOD after marrow transplant. However, the decision to proceed to transplantation in HCV-positive patients must balance the absolute risk of death from VOD against the risks of the underlying disease. In long-term survivors, HCV infection is not associated with excess mortality over 10 years of follow-up.

Donor selection procedures: is it possible to improve them?

MAJOR GOAL of transfusion medicine is to reduce the risk of transfusion-transmitted infection to as low a level as possible. One method to achieve this is through the use of appropriate donor selection procedures. In the case of transfusiontransmitted diseases for which routine laboratory testing does not exist (ie, Chagas' disease, babesiosis, and malaria as well as Creutzfeldt-Jacob disease [CJD]--a theoretical transfusion risk), these procedures are the only method available for increasing transfusion safety. For infectious diseases for which routine blood donor screening assays are currently performed (human immunodeficiency virus [HIV], human T cell lymphotropic virus [HTLV], hepatitis B and C), the importance of donor screening procedures relates to their ability to identify potentially infectious donors during the infectious seronegative window period.~,2 Since the mid-1980s, the increased awareness of the potential spread of infectious disease by blood transfusion has led to significant changes in the donor interview, implementation of the confidential unit exclusion (CUE) procedure, and a reconsideration of the impact of donor recruitment on recipient safety. This article reviews the issues related to these donor selection procedures and discusses current and future research in this field.

Performance of three generations of anti-hepatitis C virus enzyme-linked immunosorbent assays in donors and patients.

Prevention of posttransfusion non-A,non-B hepatitis in recipients of blood components improved considerably with the introduction of the second-generation of hepatitis C virus (HCV) antibody tests. In 1993, third-generation HCV antibody assays were introduced in Europe. The performance of three generations of anti-HCV enzyme-linked immunosorbent assay (ELISA) (ELISA-1, -2, -3) was compared in routine blood donor screening (99,394 donations were tested with ELISA-1, 167,999 donations with ELISA-2, and 262,090 donations with ELISA-3) and in serial samples from nine patients with documented acute posttransfusion HCV infection. Eight (0.01%) repeat donors, previously negative in ELISA-1, were found positive in ELISA-2 and were confirmed as positive in second-generation recombinant immunoblot assay and/or cDNA polymerase chain reaction. In the donor population, no difference in the sensitivity of ELISA-2 and -3 was observed. The specificity of the three generations of ELISAs was comparable (99.8, 99.7, and 99.7%). In seroconversion samples, ELISA-2 and -3 detected HCV antibodies at the same time in seven patients, but in two patients, ELISA-3 found HCV antibodies, respectively, 63 and 77 days earlier than ELISA-2 did. In the seroconversion samples, ELISA-2 and -3 were significantly more sensitive than second- and third-generation recombinant immunoblot assays. ELISA-3 did not detect more HCV-infected individuals in a donor population that previously tested negative in ELISA-2, but it did detect HCV antibodies earlier in some patients with acute HCV infection. ELISA-2 and -3 were significantly more sensitive than second- and third-generation recombinant immunoblot assays.

Look-back of anti-HCV ELISA-positive, HCV-RNA PCR-negative donors and recipients of their blood products.

To establish the infectivity of anti-HCV ELISA-positive, but cDNA-PCR-negative blood components transfused before the introduction of routine anti-HCV blood donor screening, we enrolled recipients of such blood products in a look-back programme. The blood components were donated by (A) RIBA-2-indeterminate and cDNA-PCR-negative donors, and (B) RIBA-2 and cDNA-PCR-negative donors. The look-back comprised 214 blood products from group A donors and 278 from group B. Of 211 recipients of group A components, 66 (31.3%) were available for testing. All other recipients could not be traced, had died, or refused collaboration. Of these 66, 3 patients had independent risk factors for HCV infection and were excluded. All remaining 63 recipients were anti-HCV ELISA-negative. Of 274 recipients of group B components, 84 (30.7%) were available for testing. All others could not be traced, had died, or refused collaboration. Of these 84, six patients had an independent risk factor for HCV infection and were excluded. All remaining 78 recipients were anti-HCV ELISA-negative. None of the recipients of blood products from previous donations of anti-HCV ELISA-positive, cDNA-PCR-negative, and RIBA-2-indeterminate or negative donors were HCV-infected. Donors and patients with such reactivities in anti-HCV ELISA, RIBA-2, and cDNA-PCR can be assured that they are not infected with HCV. The donors involved can re-enter the donor pool, provided that future donations are anti-HCV ELISA-negative.

Look-Back of Anti-HCV ELISAPositive, HCV-RNA PCR-Negative Donors and Recipients of Their Blood Products

Background and objectives: To establish the infectivity of anti-HCV ELISApositive, but cDNA-PCR-negative blood components transfused before the introduction of routine anti-HCV blood donor screening, we enrolled recipients of such blood products in a look-back programme. Materials and methods: The blood components were donated by (A) RIBA™-2-indeterminate and cDNAPCR- negative donors, and (B) RIBA-2 and cDNA-PCR-negative donors. The look-back comprised 214 blood products from group A donors and 278 from group B. Results: Of 211 recipients of group A components, 66 (31.3%) were available for testing. All other recipients could not be traced, had died, or refused collaboration. Of these 66, 3 patients had independent risk factors for HCV infection and were excluded. All remaining 63 recipients were anti-HCV ELISAnegative. Of 274 recipients of group B components, 84 (30.7%) were available for testing. All others could not be traced, had died, or refused collaboration. Of these 84, six patients had an independent risk factor for HCV infection and were excluded. All remaining 78 recipients were anti-HCV ELISA-negative. None of the recipients of blood products from previous donations of anti-HCV ELISApositive, cDNA-PCR-negative, and RIBA-2-indeterminate or negative donors were HCV-infected. Conclusions: Donors and patients with such reactivities in anti-HCV ELISA, RIBA-2, and cDNA-PCR can be assured that they are not infected with HCV The donors involved can re-enter the donor pool, provided that future donations are anti-HCV ELISA-negative.

Evaluation of a pooling method for routine anti-HCV screening of blood donors to lower the cost burden on blood banks in countries under development.

A pooling system was developed for use in anti-HCV screening of voluntary blood donors at the local Central American Red Cross blood banks, in Nicaragua, El Salvador and Honduras. The commercially available second generation anti-HCV screening kit from Abbott Laboratories (North Chicago, IL) was used with a modification in the initial serum dilution procedure. Pools of five sera were selected for routine screening, based on comparative studies of individual samples and of pools with different sample sizes. During the years 1993 and 1994 a total of 89, 148 voluntary blood donors were screened and a positive prevalence rate of 0.35% was established. Of the initially positive samples, 54% confirmed positive, 30% were indeterminate and 16% were negative using the Abbott Matrix test. Significant differences of positive screening prevalence rates were found in the three countries, with average values of 0.50%, 0.23% and 0.08%, respectively, in Nicaragua, El Salvador and Honduras. These initially positive samples also showed a different confirmatory pattern with a positive rate of 64% in Nicaragua, in contrast to 20% in El Salvador. Only a few samples were available for RT-PCR amplification of HCV-RNA; however, this highly sensitive method did not appear to be more helpful than serology in confirming the HCV donor status. Overall, the data obtained indicate a fluctuation of HCV prevalence in voluntary blood donors among the three Central American countries. Further, differences were found in the percentages of initially screened positives and confirmation patterns. This information appears useful for establishing criteria in future screening policies. Thus, we suggest that the use of pooling for anti-HCV screening is beneficial in countries under development, since there are potential cost savings, as well as benefits in establishment of initial prevalence rates.

Sensitivity and specificity of four assays to detect human T− lymphotropic virus type I or type I/II antibodies

Assays that detect human T-lymphotropic virus type I and type II antibody (HTLV-I/II) are widely used in the routine screening of blood donors. Four commercially available anti-HTLV-I (Fujirebio and Organon Teknika) or -HTLV-I/II assays (Murex and Ortho) were evaluated in various serum panels: A) HTLV-I-positive specimens (n = 41), confirmed by Western blot and polymerase chain reaction; B) a commercially available anti-HTLV-I/II panel; C) serial dilutions of sera from HTLV-I-positive individuals (n = 30), confirmed by immunofluorescence assay and Western blot: D) serial dilutions of HTLV-II-positive blood donors (n = 20), confirmed by Western blot and polymerase chain reaction, and E) sera from first-time blood donors (n = 1055). All four assays elicited reactions in all 82 HTLV-I-positive samples in Panels A, B, and C. Of 32 HTLV-II-positive specimens in Panels B and D, 31 (96.9%) reacted in the Organon Teknika assay and all 32 reacted in the remaining tests. Probit analysis of test results in Panels C and D indicated that the Fujirebio test was the most sensitive assay, followed by Organon Teknika, Ortho, and Murex. The specificities of Fujirebio, Murex, Organon Teknika, and Ortho tests in 1055 first-time blood donors were 99.9, 100, 99.6, and 99.9 percent, respectively. All four studied assays for detecting HTLV-I or HTLV-I/II antibodies are appropriate as screening tests.

Virology of hepatitis C virus

Hepatitis C virus (HCV) has been identified as the main causative agent of post-transfusion non-A, non-B hepatitis. Through recently developed diagnostic assays, routine serologic screening of blood donors has prevented most cases of post-transfusion hepatitis. The purpose of this paper is to comprehensively review current information regarding the virology of HCV. Recent findings on the genome organization, its relationship to other viruses, the replication of HCV ribonucleic acid, HCV translation, and HCV polyprotein expression and processing are discussed. Also reviewed are virus assembly and release, the variability of HCV and its classification into genotypes, the geographic distribution of HCV genotypes, and the biologic differences between HCV genotypes. The assays used in HCV genotyping are discussed in terms of reliability and consistency of results, and the molecular epidemiology of HCV infection is reviewed. These approaches to HCV epidemiology will prove valuable in documenting the spread of HCV in different risk groups, evaluating alternative (nonparenteral) routes of transmission, and in understanding more about the origins and evolution of HCV.

Efficacy of screening donors for antibodies to the hepatitis C virus to prevent transfusion-associated hepatitis: final report of a prospective trial.

Routine screening of blood donors for anti-hepatitis C virus (HCV) has been implemented in most developed countries. However, the independent efficacy of such screening has not been established in a controlled, prospective study. We tracked 478 patients transfused with anti-HCV-negative blood by first-generation enzyme-linked immunoassay (EIA) between July 1989 and May 1990 and compared the incidence of transfusion-associated hepatitis and HCV infections with that found among 280 patients transfused with blood unscreened for anti-HCV during the immediately preceding year. Of the 280 patients who had received transfusions before donors were screened for anti-HCV, 27 (9.6%) developed posttransfusion hepatitis and 1 additional patient seroconverted to anti-HCV without evidence of hepatitis, for a risk of posttransfusion HCV infection of 10.7% (28 of 262 recipients seronegative for anti-HCV before transfusion). Of the 478 patients transfused after July 1989 with blood screened for anti-HCV, only 9 (1.9%) developed posttransfusion hepatitis for a risk reduction of 80%. Seven of the 9 residual cases of hepatitis were caused by HCV (7 of 456 recipients seronegative before transfusion or 1.5%) for a risk reduction of transfusion-associated HCV infection of 86%. In retrospect, an anti-HCV positive donor was detected by second-generation immunoassay in 4 (57%) of the 7 HCV cases from the study cohort and in 19 of the 23 (83%) cases from whom all donor samples were available for testing in the historical cohort. No additional infectious donors were detected by third-generation immunoassay or serum HCV-RNA by polymerase chain reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of screening donors for antibodies to the hepatitis C virus to prevent transfusion-associated hepatitis: Final report of a prospective trial

Routine screening of blood donors for anti-hepatitis C virus (HCV) has been implemented in most developed countries. However, the independent efficacy of such screening has not been established in a controlled, prospective study. We tracked 478 patients transfused with anti-HCV-negative blood by first-generation enzymelinked immunoassay (EIA) between July 1989 and May 1990 and compared the incidence of transfusion-associated hepatitis and HCV infections with that found among 280 patients transfused with blood unscreened for anti-HCV during the immediately preceding year. Of the 280 patients who had received transfusions before donors were screened for anti-HCV, 27 (9.6%) developed posttransfusion hepatitis and 1 additional patient seroconverted to anti-HCV without evidence of hepatitis, for a risk of posttransfusion HCV infection of 10.7% (28 of 262 recipients seronegative for anti-HCV before transfusion). Of the 478 patients transfused after July 1989 with blood screened for anti-HCV, only 9 (1.9%) developed posttransfusion hepatitis for a risk reduction of 80%. Seven of the 9 residual cases of hepatitis were caused by HCV (7 of 456 recipients seronegative before transfusion or 1.5%) for a risk reduction of transfusion-associated HCV infection of 86%. In retrospect, an anti-HCV positive donor was detected by second-generation immunoassay in 4 (57%) of the 7 HCV cases from the study cohort and in 19 of the 23 (83%) cases from whom all donor samples were available for testing in the historical cohort. No additional infectious donors were detected by third-generation immunoassay or serum HCV-RNA by polymerase chain reaction. Implementation of donor screening for anti-HCV with a first-generation immunoassay appeared to be independently associated with an 80% and 86% reduction in the risks of transfusion-associated hepatitis and HCV infection, respectively. Screening of donors with second-generation immunoassays might have further reduced the risk by 57%. An additional 0.4% may be at risk of developing non-A, non-B, non-C hepatitis.

Unrecognized Human Immunodeficiency Virus Type 1 Infection in a Cohort of Transfused Neonates: A Retrospective Investigation

To retrospectively identify unrecognized human immunodeficiency virus type 1 (HIV-1) infection among a cohort of children transfused as neonates before donated blood was routinely screened for HIV-1 antibody. Records at a large, private, metropolitan hospital were reviewed to identify children who were transfused as neonates between January 1980 and March 1985 and discharged alive from the hospital. Multiple data sources were used to locate these children. Parents or guardians were contacted, and their children were offered HIV-1 antibody testing and physical examination. Of the 775 children identified as having received transfusions during the project period, 644 (83%) were located, and 443 (69%) were evaluated for HIV-1 infection. Among those evaluated, 33 (7%) had antibody to HIV-1, including 14 whose infections had not been previously diagnosed. At the time of enrollment, 13 children infected with HIV-1 were asymptomatic an average of 63 months after transfusion. HIV-1 antibody testing should be considered for all children, regardless of clinical status, who were transfused before routine blood donor screening was implemented in March 1985, particularly in areas with a high incidence of acquired immunodeficiency syndrome during those years.

Prevalence of HBV DNA in Packed Red Blood Cells

Assays for HBsAg, HBV DNA, anti-HBc and anti-HBs of 285 units of packed red blood cells supplied by Taegu Red Cross Blood Center were performed to evaluate the correlation between the prevalence of HBV DNA and the serologic markers for hepatitis B virus. None of 285 plasma samples was positive for HBsAg, however, HBV DNA were detected by polymerase chain reaction in 2 samples which both presented only with anti-HBc positivity. Of 204 samples tested for anti-HBs, 96 samples(47.1%) were positive and among 216 samples tested for anti-HBc, 80 samples(37.0%) were positive. Of 193 samples tested for both anti-HBs and anti-HBc, 80(41.1%) were all negative and 48(24.9%) were positive on both tests. Those samples which showed positivity only to anti-HBc were 25(13.0%). Considering the above results, transfusion-transmitted hepatitis B virus infection could be prevented by discarding anti-HBc positive blood, however, that may bring insufficient supply of donor bloods in the country like Korea where the prevalence of anti-HBc is high. Anti-HBc positive blood unequivocally positive for anti-HBs should be considered noninfectious for HBV and should be allowed to be transfused. It would reduce the amount of discarding donor blood as the routine blood donor screening tests presently used at Korea Red Cross Blood Center supplemented by anti-HBs and anti-HBc testing.

HCV antibodies in Hungarian blood donations. Experiences collected by ELISA tests, immunoblot assays and polymerase chain reaction and protocols for donor management.

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 > or = 2.5) in either of them were permanently deferred. Those negative in the supplementary ELISA or weakly reactive (1.0 < or = ER < 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.

Follow-up study of acute hepatitis C.

An extended follow-up study of hepatitis C virus (HVC) infection was conducted in Guangzhou and its nearby regions on patients hospitalized with acute hepatitis. Routine screening of blood donors for HCV was not yet instituted at the time of this study. HCV was found to be a common cause of the disease, and the infection had a close association with recent histories of blood transfusion. Sequential sera obtained from patients during hospitalization and after discharge were tested for the presence of HCV antibodies by the first and the second generation of commercial test kits, for levels of alanine aminotransferase (ALT), and for the presence of HCV-RNA. The development of HCV antibodies in some of the patients may be delayed for protracted period following clinical onset. HCV-RNA was only intermittently detectable both before and after seroconversion. Six of 33 patients studied showed seroreversion and 5 of them were accompanied by loss of HCV-RNA and serum ALT returned to normal levels. The disease persisted in 24 of 27 patients without seroreversion, accompanied by intermittent detection of HCV-RNA throughout the protracted course of the infection. Our results indicate that both EIA for detection of HCV antibodies and PCR for serum HCV-RNA should be used in combination for reliable diagnosis of HCV infection and screening of blood for transfusion.