Assessing the impact of HBV NAT on window period reduction and residual risk.
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Hepatitis B↗
Biomedical subjects
Steven H Kleinman
Publications and source records attributed to Steven H Kleinman.
Integration of nucleic acid amplification test results into hepatitis C virus supplemental serologic testing algorithms: implications for donor counseling and revision of existing algorithms.
BACKGROUND: The routine use of hepatitis C virus (HCV) nucleic acid amplification testing (NAT) donor screening assays has provided an opportunity for revision of the current HCV supplemental testing algorithm, which requires that recombinant immunoblot assay (RIBA) be performed on every HCV enzyme immunoassay (EIA)-repeat-reactive donation. The FDA has approved variance requests to use a new algorithm that eliminates the need to perform RIBA when HCV NAT results are reactive. Data are provided in support of this new algorithm. STUDY DESIGN AND METHODS: HCV EIA (including signal-to-cutoff optical density ratio), RIBA, and NAT data were compiled from 33.2 million donations screened over an approximately 4-year period by the American Red Cross and Blood Systems Laboratories. Further, donations having specific combinations of HCV EIA, RIBA, and minipool (MP) NAT results were evaluated, with more sensitive individual-donation (ID) NAT, to construct improved counseling messages for donors. RESULTS: Of 47,041 EIA-repeat-reactive donations, 49.3 percent were RIBA-positive, 17.1 percent RIBA-indeterminate, and 33.5 percent RIBA-negative. NAT-reactive rates were 79.2, 2.5, and 0.18 percent for RIBA-positive, -indeterminate, and -negative donations, respectively. The new algorithm classified an additional 1 percent of donations as HCV-infected while at the same time detecting all infections classified as HCV-infected under the current algorithm. An additional 2.4 percent of RIBA-positive, MP NAT-nonreactive donations were reactive when a frozen-thawed aliquot was retested by ID NAT. CONCLUSION: Integrating HCV NAT results with RIBA results for purposes of donor notification allows more appropriate counseling messages to be given to EIA-repeat-reactive donors. The new HCV supplemental algorithm is an acceptable alternative to the current algorithm because it provides equivalent or superior accuracy in formulating donor counseling messages and may also result in reduced costs and more timely notification of infected donors.
Algorithms↗
Two-year experience with aerobic culturing of apheresis and whole blood-derived platelets.
BACKGROUND: Throughout its system of regional centers, Blood Systems implemented culture based bacterial testing with a standardized protocol for both apheresis and whole blood-derived platelets (PLTs). STUDY DESIGN AND METHODS: After a 24-hour hold, 4 mL of PLT product was inoculated into an aerobic bottle (BacT/ALERT, bioMérieux). Cultures were incubated for 24 hours before routine product release to prevent distribution of infected products while minimizing consignee notification, product retrievals, and hospital PLT inventory problems. Initial-positives were further tested (and bacteria identified) by performing cultures from the original component and subcultures from the BacT/ALERT bottle. Results were categorized according to AABB recommended definitions with minor modifications. RESULTS: The rate of true-positive detections from culturing 122,971 apheresis PLTs was 0.017 percent (95% confidence interval [CI], 0.011%-0.026%). All true-positive microorganisms were Gram-positive with a predominance of coagulase-negative Staphylococcus and Bacillus species. Twenty of the 21 true-positive samples (95%) were detected by 24 hours but only 14 (68%) were detected by 18 hours. The false-positive rate due to contamination was 0.1 percent with the majority of isolates being skin or environmental organisms. Results did not differ significantly for whole blood-derived versus apheresis PLTs. CONCLUSION: These data corroborate the fact that the rate of detection of truly contaminated PLT apheresis products in the United States is approximately 1 in 5000 (0.02%); this is lower than the 0.03 to 0.05 percent rates that were generally quoted in the literature before the implementation of prospective bacterial culturing programs.
Bacillus↗
West Nile virus infections projected from blood donor screening data, United States, 2003.
National blood donor screening for West Nile virus (WNV) RNA using minipool nucleic acid amplification testing (MP-NAT) was implemented in the United States in July 2003. We compiled national NAT yield data and performed WNV immunoglobulin M (IgM) testing in 1 WNV-epidemic region (North Dakota). State-specific MP-NAT yield, antibody seroprevalence, and the average time RNA is detectable by MP-NAT were used to estimate incident infections in 2003. WNV donor screening yielded 944 confirmed viremic donors. MP-NAT yield peaked in August with >0.5% of donations positive for WNV RNA in 4 states. Peak IgM seroprevalence for North Dakota was 5.2% in late September. The average time viremia is detectable by MP-NAT was 6.9 days (95% confidence interval [CI] 3.0-10.7). An estimated 735,000 (95% CI 322,000-1,147,000) infections occurred in 2003, with 256 (95% CI 112-401) infections per neuroinvasive case. In addition to preventing transfusion-transmitted WNV infection, donor screening can serve as a tool to monitor seasonal incidence in the general population.
Blood Donors↗
Screening the blood supply for West Nile virus RNA by nucleic acid amplification testing.
BACKGROUND: The use of nucleic acid amplification tests of "minipools" of 16 samples to screen blood donors for West Nile virus RNA began in July 2003. We report the yield and characteristics of positive donations and the incremental yield and safety of nucleic acid amplification tests of individual donations. METHODS: Reactive minipools were analyzed to identify the individual reactive donations. For the regions with the highest yield on minipool testing, retrospective nucleic acid amplification testing was performed on individual donations that were negative on minipool testing. Reactive donations were confirmed by alternative nucleic acid amplification tests and IgM and IgG tests, and donors were followed to document seroconversion. RESULTS: From July 1 through October 31, 2003, 677,603 donations were prospectively screened for West Nile virus by minipool testing, yielding 183 confirmed viremic donations (0.027 percent, or 1 in 3703 donations). Retrospective individual testing of 23,088 donations from high-prevalence regions that were negative on minipool testing yielded 30 additional units with a low level of viremia, with 14 additional viremic units detected by prospective testing of individual donations late in the 2003 transmission season. Of all the viremic units detected, 5 percent were detected only by individual testing and were negative for IgM antibody, 29 percent were detected by individual testing after IgM seroconversion, and 66 percent were detected by minipool testing. West Nile virus infection was confirmed in both recipients of IgM-negative units that were reactive on individual testing, whereas neither recipient of antibody-positive blood components that were reactive on individual testing was infected. In 2004, prospective testing of individual donations in regions that yielded donations that were reactive on minipool testing resulted in a 32 percent incremental yield of units with a low level of viremia that would have been missed by minipool testing. CONCLUSIONS: Although nucleic acid amplification testing of minipools of blood donations prevented hundreds of cases of West Nile virus infection in 2003, it failed to detect units with a low level of viremia, some of which were antibody-negative and infectious. These data support the use of targeted nucleic acid amplification testing of individual donations in high-prevalence regions, a strategy that was implemented successfully in 2004.
Antibodies, Viral↗
A new strategy for estimating risks of transfusion-transmitted viral infections based on rates of detection of recently infected donors.
BACKGROUND: Estimates for human immunodeficiency virus (HIV)-1 and hepatitis C virus (HCV) transfusion-transmitted risks have relied on incidence derived from repeat donor histories and imprecise estimates for infectious, preseroconversion window periods (WPs). STUDY DESIGN AND METHODS: By use of novel approaches, WPs were estimated by back-extrapolation of acute viral replication dynamics. Incidence was derived from the yield of viremic, antibody-negative donations detected by routine minipool nucleic acid testing (MP-NAT) of 37 million US donations (1999-2002) or from sensitive/less-sensitive HIV-1 enzyme immunoassay (S/LS-EIA) results for seropositive samples from 6.5 million donations (1999). Incidences and WPs were combined to calculate risks and project yield of individual donation (ID)-NAT. RESULTS: The HIV-1 WP from presumed infectivity (1 copy/20 mL) to ID-NAT detection was estimated at 5.6 days, and the periods from ID to MP-NAT detection and from MP-NAT to p24 detection at 3.4 and 6.0 days, respectively; corresponding estimates for HCV were 4.9, 2.5, and 50.9 days (the latter represents period from MP-NAT to HCV antibody detection). The HIV-1 incidence projected from MP-NAT yield or from S/LS-EIA data was 1.8 per 100,000 person-years, resulting in a corresponding HIV-1 transfusion-transmitted risk of 1 in 2.3 million. The HCV incidence from MP-NAT yield was 2.70 per 100,000 person-years with a corresponding risk of 1 in 1.8 million donations. Conversion from MP-NAT to ID-NAT was projected to detect two to three additional HIV-1 and HCV infectious units annually. CONCLUSIONS: MP-NAT yield and S/LS-EIA rates can accurately project transfusion risks. HCV and HIV-1 risks, currently estimated at 1 per 2 million units, could be reduced to 1 in 3 to 4 million units by ID-NAT screening.
Acute Disease↗
Relative sensitivities of licensed nucleic acid amplification tests for detection of viremia in early human immunodeficiency virus and hepatitis C virus infection.
BACKGROUND: Screening donors for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) RNA is primarily performed on minipools (MPs) with one of two commercial nucleic acid amplification tests (NAT; Roche Molecular Systems; or Gen-Probe/Chiron). We compared these assays with respect to detection of RNA in early HIV and HCV infection. STUDY DESIGN AND METHODS: Twelve HIV plasma donor panels (116 serial samples) and 12 HCV panels (180 serial samples) were selected to optimally represent early viremia. Initial testing was performed in singlicate or triplicate on separately coded aliquots, both neat and at dilutions corresponding to MP screening (1:16 for Gen-Probe; 1:24 for Roche); 20 additional replicates were performed when discordant results were observed. Odds ratios (ORs) comparing detection of RNA by different assays were derived with logistic regression models. Differences in window-period closure and yields of assays in MP or individual-donation (ID) format were estimated. RESULTS: Differences in detection rates between Roche and Gen-Probe NAT assays were small and only observed with samples with very-low-level viremia. ORs for detecting RNA by the Gen-Probe versus the Roche assay were significant for HIV if conducted on MPs (1.8; 95% confidence interval [CI], 1.3-2.5) but not neat (1.0; 95% CI, 0.72-1.4). Odds of detecting HCV RNA were higher if the Gen-Probe assay was conducted either neat (2.3; 95% CI, 1.6-3.2) or on MPs (4.0; 95% CI, 2.8-5.8). These differences translated to <1 day window-period closure and <or=1 infection per 20 million donations. In contrast, comparisons of ID versus MP assays were highly significant for both viruses (ORs for ID vs. MP ranged from 45.3 to 93.4), with projected yields of one to two additional infections per 10 million donations. CONCLUSIONS: Differences in sensitivities of licensed NAT assays for HIV and HCV are very small and clinically insignificant, particularly when compared to differences of MP versus ID NAT screening.
Blood Banking↗
Dynamics of viremia in early hepatitis C virus infection.
BACKGROUND: It is important to characterize viral dynamics in early hepatitis C virus (HCV) infection to further our understanding of viral pathogenesis and the potential for secondary transmission in acute infection through blood transfusion or other routes. STUDY DESIGN AND METHODS: Serial units given by 77 source plasma donors who had evolved from HCV RNA-negative to HCV RNA-positive by nucleic acid amplification technology (NAT) screening with 512-unit pool-NAT or were followed from RNA detection to antibody conversion were tested by individual NAT and quantitative RNA assays. RESULTS: During the ramp-up phase when exponential growth occurs, HCV viral load doubled every 10.8 hours (95% confidence interval [CI], 9.9-12.0). Intermittent viremia was observed before the ramp-up phase in 37 of 50 panels with the earliest detectable viremic bleed occurring 63 days before the estimated onset of ramp-up. The plateau phase or high-titer viremic period that occurs between ramp-up and seroconversion was estimated to last 56.3 days (95% CI, 44.8-67.8). CONCLUSIONS: Intermittent low-level HCV viremia can occur as much as 2 months before the periods of exponential increase in viral load and the high-titer plateau-phase viremia that usually precede seroconversion. Animal inoculation studies are in progress to evaluate if transfusion of low-level viremic plasma can transmit HCV infection.
Blood Donors↗
Detection of HIV-1 and HCV infections among antibody-negative blood donors by nucleic acid-amplification testing.
BACKGROUND: Testing of blood donors for human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) RNA by means of nucleic acid amplification was introduced in the United States as an investigational screening test in mid-1999 to identify donations made during the window period before seroconversion. METHODS: We analyzed all antibody-nonreactive donations that were confirmed to be positive for HIV-1 and HCV RNA on nucleic acid-amplification testing of "minipools" (pools of 16 to 24 donations) by the main blood-collection programs in the United States during the first three years of nucleic acid screening. RESULTS: Among 37,164,054 units screened, 12 were confirmed to be positive for HIV-1 RNA--or 1 in 3.1 million donations--only 2 of which were detected by HIV-1 p24 antigen testing. For HCV, of 39,721,404 units screened, 170 were confirmed to be positive for HCV RNA, or 1 in 230,000 donations (or 1 in 270,000 on the basis of 139 donations confirmed to be positive for HCV RNA with the use of a more sensitive HCV-antibody test). The respective rates of positive HCV and HIV-1 nucleic acid-amplification tests were 3.3 and 4.1 times as high among first-time donors as among donors who gave blood repeatedly. Follow-up studies of 67 HCV RNA-positive donors demonstrated that seroconversion occurred a median of 35 days after the index donation, followed by a low rate of resolution of viremia; three cases of long-term immunologically silent HCV infection were documented. CONCLUSIONS: Minipool nucleic acid-amplification testing has helped prevent the transmission of approximately 5 HIV-1 infections and 56 HCV infections annually and has reduced the residual risk of transfusion-transmitted HIV-1 and HCV to approximately 1 in 2 million blood units.
Alanine Transaminase↗
Lack of correlation between HBsAg and HBV DNA levels in blood donors who test positive for HBsAg and anti-HBc: implications for future HBV screening policy.
BACKGROUND: Studies showing a significant correlation between hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) deoxyribonucleic acid (DNA) levels have focused on the HBV seroconversion window period. STUDY DESIGN AND METHODS: HBsAg levels relative to HBV DNA results in 200 HBsAg-positive, anti-hepatitis B core antigen (HBc)-reactive blood donations were analyzed using quantitative polymerase chain reaction (PCR) (detection limit 400 copies/mL), two research PCR assays with increasing sensitivities (65 copies/mL and 1.3 copies/mL, respectively), and a quantitative HBsAg assay; HBsAg and HBV DNA levels were correlated with HBV serologic profiles; and the potential for replacing HBsAg screening with nucleic acid testing (NAT) was analyzed. RESULTS: Serologic profiles for over 90 percent of the donor samples were consistent with chronic HBV infection. Correlation between HBsAg and HBV DNA concentrations was weak (correlation coefficient = 0.33). Thirty-six percent (72/200) of donor samples had DNA levels under 400 copies per mL. Retesting of the 72 samples by more sensitive PCR assays showed that 60 out of 200 (30%) were positive by PCR with sensitivity of 65 copies per mL, whereas 6 out of 200 (3%) required PCR sensitivity of 1.3 copies per mL for positivity. Three percent (6/200) were negative by all three NAT assays. CONCLUSIONS: HBV DNA levels in HBsAg-positive, anti-HBc-reactive blood donations can be extremely low. About 6 percent of donations would be negative by current minipool HBV NAT methods. About 3 percent of donations would remain undetected by sensitive single-donor NAT. These results indicate caution in any consideration of dropping HBsAg screening.
Adult↗
Dynamics of HIV viremia and antibody seroconversion in plasma donors: implications for diagnosis and staging of primary HIV infection.
OBJECTIVES: The characterization of primary HIV infection by the analysis of serial plasma samples from newly infected persons using multiple standard viral assays. DESIGN: A retrospective study involving two sets of archived samples from HIV-infected plasma donors. (A) 435 samples from 51 donors detected by anti-HIV enzyme immunoassays donated during 1984-1994; (B) 145 specimens from 44 donors detected by p24 antigen screening donated during 1996-1998. SETTING: Two US plasma products companies. MAIN OUTCOME MEASURES: The timepoints of appearance of HIV-1 markers and viral load concentrations during primary HIV infection. RESULTS: The pattern of sequential emergence of viral markers in the 'A' panels was highly consistent, allowing the definition and estimation of the duration of six sequential stages. From the 'B' panels, the viral load at p24 antigen seroconversion was estimated by regression analysis at 10 000 copies/ml (95% CI 2000-93 000) and the HIV replication rate at 0.35 log copies/ml/day, corresponding to a doubling time in the preseroconversion phase of 20.5 h (95% CI 18.2-23.4 h). Consequently, an RNA test with 50 copies/ml sensitivity would detect HIV infection approximately 7 days before a p24 antigen test, and 12 days before a sensitive anti-HIV test. CONCLUSION: The sequential emergence of assay reactivity allows the classification of primary HIV-1 infection into distinct laboratory stages, which may facilitate the diagnosis of recent infection and stratification of patients enrolled in clinical trials. Quantitative analysis of preseroconversion replication rates of HIV is useful for projecting the yield and predictive value of assays targeting primary HIV infection.
Biomarkers↗
Effect of a national disaster on blood supply and safety: the September 11 experience.
CONTEXT: An understanding of characteristics of blood donors donating in times of crisis may help predict blood supply safety and donor return patterns. OBJECTIVES: To characterize the volume of donations and prevalence of infectious disease markers in blood donated by US donors responding to the September 11, 2001, terrorist attacks, and to evaluate return rates in those who donated for the first time. DESIGN: Cross-sectional survey data from the National Heart, Lung, and Blood Institute Retrovirus Epidemiology Donor Study for 4 weeks before and 4 weeks starting with September 11, 2001, and the corresponding 8-week period in 2000. SETTING AND PARTICIPANTS: A total of 327065 volunteer blood donors making 373628 allogeneic donations at 5 large regional US blood centers. MAIN OUTCOME MEASURES: Changes in number of donations overall and by first-time and repeat status, prevalence of infectious disease markers, estimated risks of transfusion-transmitted viral infections, and first-time donor return rates. RESULTS: About 20000 allogeneic donations were collected weekly in the 4 weeks preceding September 11, whereas approximately 49 000 (2.5-fold increase) and approximately 26000 to 28000 (1.3-fold to 1.4-fold increases) donations were made per week in the first and in the second through fourth weeks starting with September 11, respectively. All demographic groups donated more than usual after the attacks, and after adjusting for seasonal and annual variation there was a 5.2-fold (95% confidence interval, 5.0-5.4) increase in the number of first-time donations vs a 1.5-fold (1.4-1.5) increase in the number of repeat donations made in the first week starting on September 11 vs the 4 weeks before. The weekly proportion of repeat donors returning after not donating for 10 or more years increased from 2% before September 11 to 6% in the first week starting with September 11. Donations confirmed positive for human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B surface antigen nearly tripled between 1 week before September 11 (0.1%) and 1 week after the attacks (0.3%), largely explained by the increase in first-time and lapsed repeat donors. Estimated viral residual risks increased slightly after the attacks (HIV, 1/1.5 million vs 1/1.8 million donations; HCV, 1/1.3 million vs 1/1.6 million; hepatitis B virus, 1/140000 vs 1/170000). First-time donor 12-month return rates for 2000 and 2001 were similar, approximately 28% (P =.37) for donors in the first week starting with September 11 (or September 12, 2000) and 30% (P =.69) for the second to fourth weeks. CONCLUSIONS: The September 11 events resulted in an influx of first-time donors without substantial increase in absolute risk of transfusion-transmissible viral infections. First-time donor return rates were equally relatively low before and after the attacks, suggesting that those donating in times of crisis have return behaviors similar to those of other first-time donors. Their relatively low return rates reinforce the need for education about the importance of donating regularly.
Blood Banks↗
Current and emerging infectious risks of blood transfusions.
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Blood Banks↗
Attitudes toward blood donation incentives in the United States: implications for donor recruitment.
BACKGROUND: The potential effectiveness of various donation incentive programs may vary by demographics, first-time or repeat status, and collection site. STUDY DESIGN AND METHODS: Attitudes toward future incentives were obtained from a 1998 anonymous survey sent to 92,581 US blood donors. Responses (encouraged, discouraged, no difference) to incentives were compared within demographic groups, donations sites, and between first-time and repeat community whole-blood (WB) donors using chi-square tests and logistic regressions adjusted for sample design. RESULTS: Incentives most likely to encourage donation return among all 45,588 WB respondents were blood credits (61%), cholesterol screening (61%), and prostate-specific antigen (PSA) screening (73% of men). Younger donors (< or = 25 years old) were 4 to 5 times more likely to be encouraged to donate if offered compensatory incentives (tickets to events, discounts or lottery and/or raffle tickets), gifts, or a token of appreciation than were those donors older than 55. This age effect influenced positive attitudes toward incentives in first-time donors and in donors giving at schools, universities, or military sites. Among all donors, up to 7 to 9 percent reported they would be discouraged to return if offered compensatory incentives. CONCLUSIONS: Blood credits and cholesterol and PSA screening would be well received at all donation sites. Gifts, compensatory incentives, and tokens of appreciation appeal more to younger donors. These data may allow blood centers to optimize recruitment by tailoring limited incentive resources more effectively.
Adult↗
Impact of changes in viral marker screening assays.
BACKGROUND: Monitoring the performance of routinely used infectious disease serologic tests is necessary to evaluate their effectiveness in identifying true-positive units and erroneously disqualifying safe blood donors. METHODS: With two large screening test data sets collected between 1991 and 1998 and between 1997 and 2000, the impact of changes in screening assays for HIV, HCV, and HBsAg was analyzed with regard to the prevalence of confirmed-positive, indeterminate, and confirmed-negative results and the deferral of donors with an indeterminate or negative results (donor loss). RESULTS: The prevalence of indeterminate results and donors loss increased significantly in the 6 months after introduction of an HIV-1/2 EIA. A second-generation HCV EIA increased the detection of confirmed-positive donations in repeat donors (p < 0.001) and increased the prevalence of indeterminate donations. Implementation of a third-generation HCV EIA resulted in a significant decrease in indeterminate results in first-time donors. Nonspecific test results increased when HBsAg test kits from a different manufacturer were introduced or different lots of HIV antibody screening test kits from the same manufacturer were used. CONCLUSION: Introduction of newly licensed versions of assays, switching kit manufacturers, and lot-to-lot variations have an impact on rates of deferrals of safe donors as well as sensitivity of routine screening. Before considering changes in screening tests, blood centers should be aware of, and evaluate, the potential impact on donor loss.
Antigens, Viral↗
Frequency of HBV DNA detection in US blood donors testing positive for the presence of anti-HBc: implications for transfusion transmission and donor screening.
BACKGROUND: An estimate of the rate of HBV DNA-positive, anti-HBc-positive units is important for evaluating the need for anti-HBc donor screening, especially in the context of HBV NAT. STUDY DESIGN AND METHODS: HBsAg EIA-nonreactive, anti-HBc-reactive (Corzyme, Abbott Laboratories) specimens were retrieved from a repository and were retested for anti-HBc (with PRISM HBcore, Abbott Laboratories, currently under FDA review) and anti-HBs (with PRISM Ausab, Abbott Laboratories, research assay). HBV DNA testing using a PCR assay with a greater than 95 percent detection rate of less than 50 copies per mL was performed on a subset of specimens that were PRISM HBcore-reactive and were anti-HBs- negative or reactive at less than 100 IU per L. RESULTS: A total of 395 of 1231 specimens eligible by our serologic criteria were tested by PCR. Four anti-HBs-negative specimens were PCR-positive with estimated HBV DNA copy numbers of 10 per 30 copies per mL in two specimens and 50 to 100 copies per mL in two others. The HBV DNA detection rate in anti-HBs-negative specimens was 3.7 percent, and the projected rate among all Corzyme-reactive specimens was 0.24 percent, leading to an estimated yield of 1 HBV DNA-positive, anti-HBc-positive unit in 49,000 units that were otherwise eligible for transfusion (95% CI, 1 in 16,600-1 in 152,600). CONCLUSIONS: Anti-HBc screening detects HBsAg EIA-negative, HBV-infected donors at a rate comparable to the estimated residual risk for HBV window-period infections. The low viral load in the HBV DNA-positive samples suggests that minipool NAT will not detect most potentially infectious units from anti-HBc-positive donors.
Blood Donors↗
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.
Blood Donors↗
HIV seroconverting donors delay their return: screening test implications.
BACKGROUND: The yield of HIV p24 antigen testing implemented in March 1996 has been lower than projected. One possible explanation is that HIV seroconverting donors delay their return because of the recent practice of risk behaviors and/or signs and symptoms associated with primary infection. STUDY DESIGN AND METHODS: From a database of 6.8-million allogeneic donations collected at five U.S. blood centers from 1991 to 1997, 49 HIV, 21 HCV, 32 HTLV, and 44 HBsAg seroconverters with at least three donations were identified. A statistical method was developed to investigate whether the time between a donor's last negative donation and their positive donation was significantly longer than expected based on their previous return history. RESULTS: HIV seroconverters returned on average 42 percent later than expected (p < 0.01). Although not significant, HCV seroconverters donated on average 43 percent earlier than expected. HTLV and HBsAg seroconverters did not appear to change their donation pattern around the time of seroconversion. Sixty-three percent of the HIV seroconverters later acknowledged practicing a high-risk behavior. CONCLUSIONS: HIV seroconverters delay their return around the time of seroconversion and are thus less likely to be recently infected. Unique among HIV seroconverters, this observation provides a possible explanation for the lower than expected yield of HIV p24 antigen testing and suggests that NAT may have a similar low yield.
Blood Donors↗